On a field of dirt, about a hundred octagonal white tents are lined up in neat rows. They’re weather-beaten and coated with dust, but the logo of the United Nations High Commissioner for Refugees still peeks through on their fabric rooftops, revealing their purpose. Like many refugee camps set up in recent years, this one is a mix of desperation and inactivity. Unlike most others, it’s surrounded by stadium seating.

This is the field of the baseball stadium built for the 2004 Summer Olympic Games in Athens, Greece. The stadium has gone mostly unused in the 12 years since the city spent $15 billion putting on the games. Its recent turn as a refugee camp, along with other Olympic venues in the city, has been a rare reuse of a very expensive structure built for a two-week event with seemingly little thought of what would happen after. Most of the projects Athens built for the Olympics have struggled to find a use after the Games, leaving venues barren and rotting. Notwithstanding Greece’s subsequent economic crisis and its current struggle to handle the refugee flow from various parts of North Africa and the Middle East, the Olympics have left Athens with deep and expensive scars.

Increasingly over the past half century, the Olympics have been seen as an opportunity for host cities to instigate large-scale urban improvement programs, from infrastructure building to the regeneration of entire segments of the city. The hard deadlines associated with the event can provide extra momentum to pursue wishlist projects, like new airports and transit lines, as well as the incentive to make big investments that might otherwise be politically challenging.

But sometimes the rush to prepare can result in ill-planned projects and venues with little chance of being needed after the event. Abandoned stadiums are sprinkled across Athens. Beijing’s Bird’s Nest stadium has been used only occasionally since that city hosted the Olympics in 2008, and costs the public $11 million a year to maintain. The sites of the $51 billion 2014 Winter Olympics in Sochi, Russia, mostly sit idle.

The International Olympic Committee and local organizers are now trying to avoid these kinds of planning missteps and bad investments; leaving behind a positive "legacy" is the new Olympic imperative. London, which spent roughly $15 billion hosting the 2012 Summer Olympics, has been the most proactive in thinking about its Olympic planning as a way to generate long-term benefits for the city, focusing its investments on redeveloping an economically struggling part of the city. Rio de Janeiro, days away from the opening ceremonies of the 2016 Olympics, is hoping to parlay its hosting duties into improved housing and transportation infrastructure—though there are many signs organizers are falling short.

Is hosting the Olympics worth it? Though organizers will invariably say yes, the truth is more complex than a yes or a no, and differs greatly based on the city.

Rome, host of the 1960 Summer Olympics, is regarded as the first Olympic host to use the event as an impetus for urban change, undertaking a suite of major regional infrastructure projects, upgrading roads, bridges, public transit, and airport capacity over the course of just five years. It was also the first Olympics broadcast on television around the world, beginning the era of the Olympics as a global spectacle under a bright spotlight.

Montreal’s 1976 hosting duties generated deep debt for its main Olympic stadium and related sites, costing taxpayers $1.5 billion—13 times more than originally estimated—that was only finally paid off in 2006, 30 years later. Los Angeles’s 1984 Olympics have proven to be one of the most fiscally responsible Olympics, which the city achieved by reusing many existing venues from its previous hosting stint in 1932 and other sites throughout the city. It’s often celebrated as an example of how not to saddle a city with expensive and underused sports facilities, and, perhaps most importantly, as the first Olympic Games to turn a profit for the host, creating a $225 million surplus—and helping to establish the Olympics as a moneymaking opportunity.

More than any other two-week period, the Olympic Games result in choices, plans, and projects that can affect a city for generations—for the better and, more often, for the worse.

More recently, host cities have aspired to use the Olympics to make a broader urban impact. The high water mark is Barcelona in 1992, where officials focused on redeveloping parts of the city, particularly a former industrial area along the waterfront that became a mixed-use neighborhood to house the athletes’ village. The city subsequently became a major tourist destination. It also exceeded its original budget by roughly 266 percent, according to a recent study. Regardless, the host cities since Barcelona have all tried to emulate this urban redevelopment success.

For the modern era, Athens and London offer two contrasting examples of what cities can get from hosting the Olympics—a collection of unusable, debt-collecting sports venues or a catalyst for the regeneration of a huge swath of the city. But even within each of these extremes, there are shades of failure and success, of mismanagement of public funds and prudent investments in the public interest, of projects that benefit the many or just a few. Each city offers lessons for others hoping to use such megaevents to spur urban improvements. More than any other two-week period, the Olympic Games result in choices, plans, and projects that can affect a city for generations—for the better and, more often, for the worse.

An indoor tent city fills the two-story domestic arrivals and departures building of the former Ellinikon International Airport in Athens. Hundreds of refugees—mostly Afghans—are camped in and around the airport's facilities, which had been empty since being decommissioned in 2001. Dozens of vinyl tents fill the ticketing halls, and still more sit outside in rows along an asphalt drop-off zone beneath a big sign for Olympic Airways. Women wash dishes in buckets. A small toddler, no more than two years old, sits alone on a curb.

Beyond, on the empty tarmac, two men from Afghanistan walk through the shadeless heat with towels draped over their heads. They speak little English, but there's not much to say on this desolate walk. Greek police officers in an air conditioned single-wide mobile office barely look up as the men pass through a checkpoint between the airport's buildings and its wide concrete runways. In the distance are signs of the airport's second life: the baseball and field hockey stadiums built, along with a handful of other venues, for the 2004 Olympics. They'd been disused ever since. And then the refugees started coming.

The stadiums now house hundreds of refugees from across North Africa and the Middle East. There are an estimated 1,300 people living in the stadiums and the airport, and tents fill nearly every possible shaded pocket of these buildings. UNHCR tents and structures are set up on what was an Olympic concourse connecting the stadiums, and laundry hangs on the barbed wire fences that contain the area.

In the field hockey stadium, rugs and sheets are tied to the railings of the mezzanine to block the strong summer sun. In the former concessions areas, aid organizations hand out pita bread and other supplies. Old men sit on the ground around a chessboard while a woman uses a hand brush to sweep the dusty concrete floor around her tent.

"The venues are at least being used for something," says Nicolas Souliotis of the National Center of Social Research in Greece, who’s studied the evolution of urban policymaking in Athens before and after the Olympics. He’s trying hard to find a bright side to the current situation at the airport and the city’s largely disappointing Olympic legacy.

That’s not to say Athens didn’t get some tangible benefits from its Olympic efforts: the new airport, an expansion of the transit system with new tram and subway lines, the completion of about 130 miles of new roads and highways, including a peripheral road on the outskirts of the city, and new pedestrian connections to the city’s main archaeological sites. They have changed both the form and function of Athens. On the city’s to-do list since the 1970s, they became key elements of its bid for the 2004 Olympics (as well as a previous failed bid for the 1996 Olympics). "The games played the role of a catalyst," Souliotis says.

"I came to the conclusion that there is no bigger bubble than the Olympic Games."

"We saw in 1990 our desire and heritage alone would not guarantee the games," Gianna Angelopoulos, president of the Athens bid committee, told the press in 1997, shortly after Athens won its bid for the 2004 games. "We Athenians looked at our city with a more critical eye. We said we must improve on our city to make it worthy of its past. This was a new bid for a new city."

The new city she hoped for hasn’t materialized. Many of the 20 or so sports-related projects built for the 2004 Olympics—and dozens more training facilities scattered throughout the region—are struggling to find purpose. Part of this was poor planning from the start: Greece lacked a strong enough culture for sports like baseball and kayaking to need permanent sport-specific stadiums. Souliotis argues that a bigger part of the problem was the significant gap between what organizers and planners proposed and what was actually built. The original master plans for both Olympic bids concentrated the sports facilities in two areas: one near the waterfront to the south of the city center, with the intention that the projects would better link the city to the water, and the other located slightly north of the city center, around the site of an existing Olympic-size stadium and sports complex. But due to environmental concerns about building on sensitive waterfront areas and a general outcry for what some saw as a more equitable distribution of sports facilities and their potential redevelopment opportunities, this concept of two poles was eventually abandoned. Instead, the facilities were scattered throughout the city, and even into surrounding suburban areas. "Where they found spaces, they put venues," Souliotis says.

After the Olympics, a state-run organization was set up to handle the redevelopment and reuse of these venues. The distant or poorly connected nature of many of the venues—as well as their generally large size—made them less than attractive to developers who might have wanted to reuse them. In addition, Souliotis says, legal complications with building licenses and permits, environmental issues at venue sites, community opposition movements, and the generally dysfunctional relationship among many public agencies has hindered the redevelopment of many venues.

It didn’t help that by 2010 the country’s national debt had risen to such a degree that it required a bailout from the International Monetary Fund, the European Central Bank, and the European Union, which effectively closed the country off from international capital markets. (The subsequent second and third bailouts further limited the appetites of investors.)

Many of the Olympic venues are visibly suffering from their years of neglect. The main Olympic complex is like a museum of dying stadiums. Located about five miles north of the city center and directly accessible by the Metro, the complex is home to many of the Olympics’s largest venues, including the soccer/track and field stadium that was also used for the opening and closing ceremonies, the basketball and gymnastics stadium, the 16-court tennis center, the aquatics center, and the track cycling velodrome. All but the tennis center were already built before the Olympics, hosting various international sporting events in the 1990s. For the Olympics, these venues, and the roughly 200-acre site itself, were significantly renovated by architect Santiago Calatrava. Dramatic new roofs with huge steel arches were added to the main stadium and the velodrome, and large sculptural elements and canopies were added throughout the site, all in gleaming white.

This all makes for a striking entrance to the park. From the Metro station, it’s a short walk until you pass under a wide arching canopy into the site. A security fence has been tacked on after the fact, and on a recent day a group of teenage boys could be seen ripping part of it down. Once inside the fence, the first experience of the park is what’s known as the agora, a swooping walkway shaded and framed by a tall arched pergola, its metal shades rusting and creaking in the wind. Wading pools line its side, though only a few still have water. Beyond, the park opens up, and the stadiums and venues themselves sit mostly along its perimeter.

Conspicuous at one end is the unused velodrome, sealed off on all sides and a widely cited example of a venue the city didn’t need. "It makes the whole area very light and very beautiful. But it is useless," says Roy Panagiotopoulou, a professor at the University of Athens who has tracked the costs of the Olympics and the post-event burden many of the venues have left behind. She argues that the planning for the event simply didn’t consider what would happen to many of these venues after the Olympics were over.

Many of the 20 or so sports-related projects built for the 2004 Olympics—and dozens more training facilities scattered throughout the region—are struggling to find purpose.

Next to the empty velodrome is a pair of outdoor pools, each still filled with water. In one, a swimmer and a coach are training, but the other is slowly rotting, its seating falling apart from below, with electrical lights haphazardly hanging from the rafters and blowing in the breeze. The indoor aquatics center was a more lively scene on a recent weekend. The pool was playing host to a Special Olympics event and a modest crowd cheered on heats of the men’s 100-meter backstroke. Other areas of the building are also being reused. One section has been turned into a boxing gym, with a ring and a line of punching bags. Another is a weightlifting gym. An indoor climbing gym has also been built into one nook, and children at a birthday party were being taught how to climb its walls. A litter box tucked in a corner behind the diving platforms suggests some of Athens’s many feral cats have found a home.

The basketball stadium next door is fenced off, but it serves as the home court for a local basketball team, and it has also hosted Cirque du Soleil events and concerts in the past. The main stadium is used by a local soccer team, and graffiti covers its outsides. Tucked in another corner, fenced off from the rest of the park, is the tennis center, which is now used as a private club.

Aside from the aquatics center, the area feels like a forgotten part of the city, devoid of any activity on all but very few days throughout the year.

But then, as the sun starts going down, the park gradually comes to life. Joggers run around, beating a path in the gravel around the soccer stadium. Cyclists lean into curves on the smooth concrete. Families stroll along the wide promenades and past the empty buildings. Under the agora, teenagers with headphones practice dance moves on inline skates, children play soccer and ride bikes, parents and adults congregate for picnics and people watching.

Panagiotis Chrysochoos is here with his wife and their two children, ages 10 and 11. His family comes out to the park two or three times a week in the spring and summer, though it gets too windy in the fall and winter. There aren’t a lot of big open spaces for kids to play in this part of Athens, he says, and despite its abandoned feel, the park is a surprisingly safe space for his kids to run wild. "They’re around here somewhere," he says.

Other Olympic venues around the region haven’t had this type of bottom-up reuse, though some are at least occasionally reused. The table tennis and gymnastics venue in the Galatsi neighborhood, five miles north of the city center, is surrounded on all sides by a security fence, but was recently used as the set of the Greek version of the television singing competition X Factor. To the south, along the waterfront, the beach volleyball stadium rusts in the salt air, while adjacent waterfront facilities host a children’s summer school. A 10-minute walk away, a 3,700-seat stadium built for tae kwon do and handball competitions was recently being prepped for a concert. Across town, the former badminton venue has been adapted into a theater, and is seen by many as the most viable reuse of an Olympic project—though the project’s conversion from a temporary venue in a public park to a permanent, privately operated theater has resulted in a court case and a demolition order.

After several attempts and reorganizations, a state-run organization called the Public Properties Company is now tasked with finding new uses for about a dozen of the sports venues built for the Olympics, including the equestrian center a 45-minute drive from the city center, the stadium-turned-X Factor set, and a 2,000-hectare rowing center 30 miles outside of the city. Given their sometimes far-out locations and the 12 years of disuse, many of these properties are challenging sales. Public Properties Company officials say that more reuse of these sites is planned, including "the hosting of big TV live shows for next year" and other "big events."

The Olympics can catalyze and accelerate large-scale urban projects, but there’s also a danger in using an event with a very tight timeline and short window of activity to bring about projects that can affect cities for decades.

One potential reuse success is the Ellinikon Airport site. In June, the government and a group called Lamda Development finalized a deal to redevelop the 1,500-acre site into a new neighborhood and public park. The exact details of the project haven’t been explained, but the site will include a nearly 500-acre park, residential areas, hotels along a revamped waterfront, and a variety of entertainment, sports, and health care facilities. Lamda purchased the land for roughly $1 billion, which some say is far less than its market value, and the whole project is expected to cost around $10 billion in mostly private but also some public money. Officials from the company declined to elaborate.

Whether these plans are fully realized remains to be seen, but agreements have been signed and money invested in such a way that the former airport and its Olympic venues seem likely to find new life in the coming years.

The future of most other Olympic venues is less clear. Many will probably remain underused and unable to integrate with the neighborhoods around them. Panagiotopoulou, who has been tracking the money spent to host the 2004 event, says the roughly $15 billion Greece invested has had only limited urban benefits for Athens in the long run. "I came to the conclusion that there is no bigger bubble than the Olympic Games," she says.

From within London’s Queen Elizabeth Olympic Park, there’s hardly a direction you can look without seeing a crane or construction site. Buildings are rising all around and within the site of the 2012 Summer Olympics—from mixed-use buildings to office complexes to luxury housing to so-called artist’s lofts that are actually just more luxury housing. Though Britain’s recent decision to leave the European Union has slashed housing values, the development boom that’s been underway is not especially surprising for a high demand city like London. It is, however, something of a sea change for this specific part of London, the long-depressed district of Stratford. It’s in the borough of Newham, where poverty and unemployment have historically ranked among the highest in all of England. The Olympics have kickstarted a developmental rebirth of sorts in East London.

"The center of gravity has shifted in the easterly direction," says Bob Allies, a partner at Allies and Morrison, a London-based architecture and urban planning firm that was involved in master planning the 2012 Olympics. "Something like the games, it just changes the map."

The Olympic park itself is a stark contrast to Athens. Instead of a collection of disused stadiums with a park wedged in between, London’s park is actually a park, with playgrounds, green spaces, a meandering river, and varied landscapes for walking and recreating. The few sports venues that weren’t removed after the Olympics are pronounced but not dominating.

This is all by design. London is novel among recent Olympic hosts in that its plan for the Olympics was focused primarily on what would happen after the games—how the development of the Olympic venues and park and infrastructure could create long-term benefits for the community and the city as a whole. This planning was partly a requirement of what’s now known as the Olympic Games Impact program, a legacy-focused initiative launched by the IOC in 2000 calling on host cities to engage in ongoing evaluation of the planning, execution, and aftermath of the Olympics, starting during the bidding process and continuing through two years after the event. London embraced the philosophy behind this program, planning its stint as Olympics host in the service of broader urban goals. London’s could be considered the first truly legacy-focused Olympics.

Leaning against a wall in the offices of Allies and Morrison is a large triptych of models, each an aerial view of the Olympic park site. One is set in 2006, the baseline conditions from around the time London was officially selected to host the 2012 Olympics. The second model is set in 2012 and shows what the area looked like during the event. The third is set in 2024, the year when, according to the Olympics master plan, most of the housing and real estate development in and around the Olympic site will be complete. "We always had our conversations around these three images," says Allies. The designers aimed to be constantly conscious of what the area had been and what it could be.

London is novel among recent Olympic hosts in that its plan for the Olympics was focused primarily on what would happen after the games.

Before the Olympics, this part of East London was part industrial and part wasteland. It was "a place you put all the things you don’t want anywhere else," says Allies—things like power production, rail lines, garbage processing, fish factories. Situated in the valley of the River Lee, the area had been a utilitarian space since the 1800s, and was always seen as being on the fringe of the city—both geographically and economically.

Now the city is spreading out towards that fringe. The development is much needed, as this part of East London has lagged the rest of the city, according to Penny Bernstock, a professor at the University of East London who specializes in housing and urban regeneration. "There’s been long-term unemployment and an issue of a skills gap for the people living there and the kinds of jobs being created. You’ve also got a problem of housing, where Newham has the worst indicators of housing in the country—some of the highest levels of overcrowding, some of the highest numbers of people on housing waiting lists," says Bernstock.

The city had long wanted to develop East London, even as far back as the years after World War II, according to Ricky Burdett, professor of urban studies at the London School of Economics and chief adviser on architecture and urbanism for the 2012 Olympics. The Olympics were seen as a way to finally implement that type of regeneration. Breathing new life into East London and improving its economic ties to greater London became the core concept in the city’s bid to host the Olympics, first drafted in 2003. "It fits into quite a deep-set attitude of what London wants to be," Burdett says.

Now, four years after the Olympics, Queen Elizabeth Olympic Park is a huge and varied public space. The cleaned River Lee winds through its center, and pathways cut through plushly landscaped riverbanks, gardens, and playgrounds. School groups tour the wetlands and meadows, and tourists ride rented bikes along the river. Its spaces are alternately wide open and tucked among wildflowers. Trains rumble underneath and around the park to two major rail stations, and the construction cranes lean over its edges.

One section of the park still bears the heavy hardware of the Olympics, with the main stadium, set to become the home of the West Ham United soccer team in August, and the aquatics center, designed by Zaha Hadid. Towering overhead is the gargantuan and somewhat absurd ArcelorMittal Orbit—"the UK’s largest sculpture"—which has recently been further bangled with a 584-foot-long tube slide. A handful of other venues remain in other parts of the park as well. People with fancy bikes ride at the velodrome and outdoor cycling track, and the field hockey and tennis center is nearby. Across the river is the Copper Box Arena, a multi-sport gym and theater space open to the public, and the former media center, which is being converted into office space and a technology hub.

A significant part of the park is still under construction. Crews are madly building the International Quarter, a 22-acre cluster of office buildings with space for roughly 25,000 employees. On vacant spaces around the aquatics center and stadium, a cultural center called Olympicopolis will house a new outpost of the Victoria and Albert Museum (in collaboration with the Smithsonian), new campuses for University College London and University of the Arts London, and a 600-seat contemporary dance theater, all set to finish construction by 2022. The core of a 42-story luxury apartment and hotel tower is also rising; the building is expected to open in 2018. Next to the velodrome is the construction site of Chobham Manor, the first of five neighborhood developments to be built in the park. It will add about 800 units, ranging from one to five bedrooms, with prices starting around $385,000. (The first phase of the development has already sold out.) Bernstock says the recent Brexit vote will likely affect the development to come—and its potential buyers. "I think we can assume that construction will slow down," she says. "An important market for the purchase of properties in Stratford has been overseas investment and it is likely to become more difficult for them to access loans to purchase such properties."

London is a city that used its Olympics to pursue a long-sought project, the regeneration of East London. Athens is a city that allowed the conceptual framework behind its Olympics to slowly fall apart.

Just outside the park’s border is a Westfield mall, a half-indoor, half-outdoor shopping megacomplex, planned the year before London bid for the Olympics, and widely seen as a significant investment in a then-struggling Stratford. Across the nearby rail lines is the athletes’ village, rebranded as East Village, with about 2,800 homes built in mixed-use courtyard apartment blocks, each 10 stories high. It’s mostly rentals, half set at market prices and about a quarter set aside as social housing. Kids kick a ball in a grassy park space on its periphery and men match each other push-up for push-up in an outdoor gym. A few shops and restaurants have begun to open in the ground-floor retail spaces. A barista at a newly opened coffee shop says weekday business is a bit slow and mostly driven by locals, but the weekends are busy with tourists and visitors. The business was solicited to open an outpost there, lured in primarily, she says, by the prospect of getting a liquor license that would be prohibitively expensive in other parts of London.

During the day, the village is mostly quiet, though people are streaming to and from the adjacent Stratford International train station and the mall. The main street cutting through the mostly pedestrian-only site has a small outpost of a chain grocery store. As work gets out, a few people settle on the patio of Neighbourhood, the bar next door. Overall, the village is shiny and somewhat sterile, especially compared to the more compact and economically varied neighborhood that predated the park.

The Olympic site and its fringes are expected to see the development of about 10,000 new residential units by 2030, some directly related to the Olympic planning and some developed privately. This trickle-out real estate development is one of the positive benefits of the Olympics, says Peter Tudor, director of venues for the London Legacy Development Corporation, the organization in charge of the planning and development of the park. "They’re not specifically driven by us," Tudor says, "but they’re here because the Olympics happened."

The construction at the park is clearly visible through the window of The Eagle, a pub just on the other side of the train tracks, in a modest low-rise neighborhood of mews houses and maisonettes. A few patrons, middle-aged men from the neighborhood, say all the new development hasn’t translated into any grand benefits for the areas surrounding the park. They worry it’s driving up prices across Stratford and pushing longtime locals out.

Bernstock says displacement is inevitable. "The very nature of the development is they’re less likely to be able to live in Stratford," she says. "There’s all these people in housing need, and the kind of housing being built on the park and surrounding areas is not mapping onto the needs of those people, in terms of affordability."

In fact, many people lost their homes ahead of the Olympics. In 2011, residents began to be cleared out of the three 22-story towers of the Carpenters Estate public housing complex near the east side of the Olympic site to make way for a University College London campus—a plan that eventually fell through. During the Olympics, the BBC used the top five floors of one of the towers as television broadcasting studios. The towers have been mostly empty since. A small number of people are evidently still living in them; laundry hangs on a few of the towers’ balconies. Maintenance workers seen outside one of the towers claim to have signed a nondisclosure agreement not to reveal whether or how many people are occupying the buildings.

In 2007, about 430 residents were relocated from the Clays Lane housing cooperative, which was demolished to clear space for the development of the athletes’ village. Julian Cheyne was one of the displaced residents, and he’s become something of an Olympic watchdog, fact-checking claims about the impact and legacy of the event. He says the widely touted legacy claim that the Olympics will have helped create 10,000 new housing units in the area distorts the truth. Many of the buildings rising around the Olympic site were planned and permitted before London won the bid to host the games back in 2005, and some from before the city even decided to bid. A previous master plan for the area, drafted before the Olympic bid, called for roughly 13 million square feet of residential, commercial, and retail development. Based on Freedom of Information requests he’s made to the London Legacy Development Corporation, Cheyne tallies that the actual amount of housing being directly built as part of the official legacy plan is somewhere between 5,650 and 6,800 units, with plans for some of the housing still in flux.

The Olympic site and its fringes are expected to see the development of about 10,000 new residential units by 2030, some directly related to the Olympic planning and some developed privately. "They’re not specifically driven by us," says Peter Tudor, director of venues for the London Legacy Development Corporation, the organization in charge of the planning and development of the park. "But they’re here because the Olympics happened."

Targets for affordable units in the developments have also changed since plans were first written, dropping from 50 percent to as low as 28 percent in some projects, and Cheyne says that will likely mean there’s a net loss of affordable housing in the area. "You’re not getting the replacement housing which you would have got if you’d just let the area alone," he says.

"We need to intervene in the housing market if we don’t want to push local people out," Bernstock says. She expects the displacement of people to continue. She argues that the legacy planning hasn’t done enough to protect residents from being priced out, nor to develop jobs for lower income and lower skilled residents.

"I think that the Olympics was very important in accelerating the pace of change and bringing about a more coordinated approach to change in the area," she says. "But it’s property-led regeneration, in the end. And that will never meet the needs of local residents."

The post-event Olympic Games Impact report for London was released in December. It covers the 12-year period between 2003 and 2015, looking at quantitative data for 67 indicators of economic, social, and environmental conditions, and was conducted by researchers from the University of East London, independently from the Olympic organizers and the government. Reflecting on the years after the Olympics, the report is largely positive, arguing that the event spurred a tangible regeneration in East London, that its sporting venues are all secure in management and use, and that poverty and social exclusion rates have fallen in the areas around the Olympic site.

"I think London was successful because legacy was talked about from day one," says UEL professor Allan Brimicombe, who led the OGI studies. "At least 99 percent of what was planned for the games has a legacy rationale to it, whereas in previous games that hadn’t been the case."

But he also notes that the parameters of the study required only the consideration of quantitative data, and therefore ignored other information that could have put some of these changes in perspective. For example, though the Olympic site has been designed to physically connect with the surrounding neighborhoods, its newer and more expensive developments feel starkly different from the existing city.

Burdett says it’s too soon to expect these urban transformations to stitch themselves into the city organically. "I think that’s going to take quite a lot more time," he says. "Over the next five to 10 years, those places are going to feel much more coherent and consistent."

Overall, he says, the Olympics have achieved their main goal, which was to accelerate the regeneration of the areas surrounding the Olympic site. "It’s rebalancing a fundamental inequality between East and West London," Burdett says.

Future Olympic host cities are already emulating London’s approach to using the games for broader urban transformation. Los Angeles, the official U.S. candidate city for the 2024 Summer Olympics, is building its bid around accelerating the city’s existing long-term plans for a wide array of public transit projects and citywide sustainability efforts. Tokyo, set to host the 2020 Summer Olympics, is using the event to spur the redesign and rebuilding of the damaged Tokyo Metropolitan Expressway, limiting vehicle use in the center of the city and encouraging residential growth in the urban core.

Rio de Janeiro, the 2016 host, has tried to use its Olympic preparations (and those related to the nation’s 2014 hosting of the FIFA World Cup) to dramatically reshape the city. Preparations include the construction of dedicated bus rapid transit lines and metro rail, redevelopment of the city’s port, widening of a major highway, urban renewal projects in neighborhoods across the city, and the broad development of an Olympic park and athletes’ village on the outskirts of the city.

But the city’s preparations have been widely criticized for inequitable design, the displacement of the city’s most vulnerable people, a heavy police presence that’s militarizing public space, and an overall legacy that serves a limited population—on top of Brazil’s ongoing economic and political scandals. Carlos Carvalho, the developer who owns much of the land being developed for the main Olympic park, is not shy about his hope that the legacy of the Olympics will be a neighborhood for the rich. "We think that if the standards were lowered, we would be taking away from what the city—the new city—could represent on the global scene as a city of the elite, of good taste," he told The Guardian. "For this reason, it needed to be noble housing, not housing for the poor."

For all the momentum they can bring, the Olympic Games are a rather crude tool for urban development.

Burdett sees London’s legacy-focused approach being perverted in Rio de Janeiro. "The language is nearly the same: we’re trying to create a piece of the city," he says. "The reality is drastically different."

Though the host cities’ local organizing committees are ultimately responsible for the impact of the Olympics, many argue that the rules governing this and other megaevents be more explicit about how the planning should affect the city in the long term.

Jules Boykoff, author of Power Games: A Political History of the Olympics, says that reform is needed within the IOC to have more transparency around what specific urban factors are considered during the host city selection process. Others have suggested that the 12-year evaluation timeline of the Olympic Games Impact program should be much longer. Brimicombe has also made suggestions about how the Olympic evaluation and bidding processes can be improved by including more documentary evidence of the impacts of the event on host cities, and says the IOC is beginning to modify its approach. "They are taking a more holistic view," he says. But there’s still room for improvement.

The IOC declined requests for an interview, but issued a statement arguing that the Olympics "need to create more than just good memories from 16 days of competition. This is why emphasis is placed on promoting a positive legacy from the Olympic Games to the host cities and host countries. With that in mind, the IOC has worked hard to help current Games organizers, as well as applicant/candidate cities, look at what they believe planning for and hosting the Games, as well as simply bidding for them, can do for their citizens, cities, and countries." In regards to only requiring a post-event evaluation for three years after the Olympics, IOC representatives noted that the organization "recommends" to host cities that the study period be extended. No host city has yet taken this advice.

In her book Planning Olympic Legacies, Eva Kassens-Noor argues that the IOC has major influence over cities as they plan for the Olympics, and that unless the cities have a clear plan for what they want in the long term, they can easily be swallowed up in the short-term, event-focused planning that has left many host cities with unusable projects and deep debts.

Olympics researchers Stephen Essex and Brian Chalkley argue that host cities should think of their potential urban legacy as something they need and could achieve even without the Olympics. "The Olympic legacy is most effective and pronounced where it goes with the grain of wider urban policies and developments," they write.

London is a city that used its Olympics to pursue a long-sought project, the regeneration of East London. Athens is a city that allowed the conceptual framework behind its Olympics to slowly fall apart.

The effects are clear on the ground. In London, a massive real estate development is underway and having a transformative, though not universally welcomed, effect on its surrounding areas. In Athens, the underused venues of the Olympics have burdened many neighborhoods with hulking projects that only sporadically serve the needs of the city’s people.

The fast-forward urbanism of the Olympics is fraught with potential missteps, and they can be seen in every recent host city. The Olympics can catalyze and accelerate large-scale urban projects, but there’s also a danger in using an event with a very tight timeline and short window of activity to bring about projects that can affect cities for decades. For all the momentum they can bring, the Olympic Games are a rather crude tool for urban development. If they become the tool of choice, the cities using them should proceed carefully. Perhaps the only conclusive evidence from previous Olympic hosts is that the results will be complicated. But if they're planned from the start to serve the needs of the cities that host them, there will at least be a chance that the Olympics leave behind something more useful than debts and empty stadiums.

Editor: Sara Polsky

Photo Editor: Audrey Levine