In 1992, the Baltimore Orioles opened their baseball season at a brand new stadium called Oriole Park at Camden Yards, right along the downtown harbor. The stadium was small and intimate, built with brick and iron trusses—a throwback to the classic ballparks from the early 20th century. It was popular right from the start. “It’s magnificent in an understated, baseball-only, real-grass, open-air, quirky, cozy, comfortable, cool sort of way,” wrote Tim Kurkjian in a glowing Sports Illustrated review.

No one knew it at the time, but Oriole Park at Camden Yards would change the design of ballparks all around the country. Its success set off a building boom in baseball, as city after city built new stadiums based on the architectural principles laid down in Baltimore. That design revolution would fundamentally change the experience of going to the ballpark and the relationship between baseball and cities.

From Urban Ballparks to Concrete Donuts

In the early 1900s, most baseball stadiums were relatively small and built in dense urban neighborhoods, which shaped their design.

But in 1950s and 60s, as white populations fled downtown for the suburbs, baseball followed them. Teams built stadiums on the edge of cities where they were more accessible to middle class fans who drove to games in cars.

These massive new, multipurpose stadiums were designed to be house both baseball and football. They were set apart on large plots of land, often surrounded by acres of parking — completely different from their urban predecessors.

But these multipurpose stadiums, or “concrete donuts” as they were sometimes called, really weren’t great for fans of either sport. They were perfectly round to fit both a football field and a baseball diamond, but that meant that the seats were often really far away from the action, or angled in weird directions. They were also really large for baseball, with 50,000+ seats (versus 25-30K for urban parks), which left them looking big and uniform while feeling empty and impersonal.

The S-Word

For a long time, the Orioles played in their own concrete donut, Memorial Stadium, along with Baltimore’s football team, the Colts. When the Colts left for Indianapolis (citing Memorial Stadium as a reason), many began to fear the baseball team might also “leave town for greener ballparks,” says Larry Lucchino, who was President of the Orioles in the late 1980s. The team’s owner Edward Bennett Williams wanted to build a nice new multipurpose stadium — with that, the city could try and court another football team back to Baltimore. But Lucchino had another idea:

“Let’s look at the most successful baseball franchises out there. The Yankees in Yankee Stadium. The Cubs in Wrigley Field. The Red Sox in Fenway Park. And what did they have in common? They all played in a baseball-only facility, a facility that was designed for baseball and did not compromise architecturally for other other sports.”

Those ballparks were old and idiosyncratic, and Lucchino argued that a new ballpark could carry on that tradition and aesthetic — “an old-fashioned traditional baseball park with modern amenities,” he recites. “If we used that phrase once we used it ten thousand times.” He was so committed to this idea he banned Orioles employees from using the word “stadium” and collected fines when people said the “s-word” around him.

The new ball park would be built right downtown. This was seen as a way to revitalize downtown Baltimore, and the team managed to secure public funding. The Maryland Stadium Authority hired architects from Populous (known at the time as HOK Sport) to work with the Orioles own design director, Janet Marie Smith.

It was Smith’s job to ensure that the team stayed true to Lucchino’s vision of an old fashioned park. One of her key observations was that older ballparks were wedged into tight urban environments, and shaped by surrounding structures. Each ballpark had different dimensions, depending on the plot of land on which it was built. In most sports, the playing field is completely standardized, but not baseball.

“There are rules about the infield,” Smith explains.”You’ve got to have 90 feet between the bases 60 feet six inches from home plate to the pitcher’s mound. But there’s no rule about the outfield.” This fact led to a lot of irregular shapes and dimensions. That variety means that some ballparks are better for pitchers while others are better for hitters. Some parks give up more home runs to right-handed batters, others to lefties, and so forth. “The park itself really does shape the outcome of the game,” says Smith.

To make the new ballpark fit the neighborhood, they decided to leave an old abandoned brick warehouse in place and shape the field around it. This choice ended up informing the rest of the design, right down to the shape of the stands and the construction materials (brick and iron).

Attendance at games shot up in the new stadium. In their first two seasons at Camden Yards, the Orioles had the second-highest attendance in the major leagues. Pretty soon other teams started to take notice and they sought to emulate Baltimore’s success.

In 1994, another old-fashioned baseball-only ballpark called Jacob’s Field opened in downtown Cleveland. And that was just the beginning. Pretty soon, all new ballparks were being designed to look like old ones.

In the 25 years since Camden opened there have been 20 new stadiums built, and there is not a concrete donut in the bunch. Like Camden Yards, most of these new stadiums have been built close to city centers — and most have been paid for in part with public money.

Cities were sold on the idea that downtown parks would be a boon for everyone involved. “Here’s something that’s supposedly a win-win-win,” explains Neil DeMause, a journalist who studies stadium economics. “It’s a win for the team because they get you know new revenue. It’s a win for the fans because they get a stadium that they love, and it’s a win for the city because they get to revitalize a district.”

But it’s not clear that building a baseball stadium is the best way to revitalize a neighborhood — most local businesses can’t rely on baseball crowds showing up for 81 games a year. And then there is the question of whether the public should have to pay for privately owned buildings. Sports may be important for city identities and fans, but teams are still businesses — owned by very wealthy individuals.

Greener Ballparks

Difficult questions about function and funding have not, however, stopped the retro ballpark building boom. Across the country, baseball teams have done everything they can to follow the Camden template. They even go to the same architecture firm, Populous (formerly known as HOK Sport).

These new Populous ballparks are small and old fashioned-looking but they also feature modern amenities—comfortable seats and fancy foods. And while designed to be different, they tend to follow a similar aesthetic format, featuring a lot red brick and green-painted iron. These new parks also feature asymmetrical playing fields, which are in many cases dictated by the surrounding cityscape.

San Diego’s Petco Park, for instance, has a left field line informed by the adjacent Western Metal Supply Company — the team just painted a yellow stripe down the corner of the warehouse in lieu of a foul pole.

AT&T Park in San Francisco is squeezed right up against the San Francisco Bay and the right field line goes all the way to the water. This gives fans a spectacular view while creating a unique local drama: splashdown home runs. When someone hits a ball into the bay, a flotilla of kayakers descend on the souvenir.

But not all of the new retro ballparks are so successfully integrated with their urban context. While Citi Field (the new Mets Stadium in Queens) has an asymmetrical shape, it was artificially derived. Its odd dimensions don’t respond to facets of the built environment.

Examples like that illustrate just how much the Camden template itself has become dominant over the ideas that drove it in the first place, like: creating something specifically fitted to a given city. Mark Lamster, Architecture Critic at the Dallas Morning News, is critical of this new orthodoxy. “They all have the same DNA, they all kind of look kind of the same, except the whole idea is that each one is idiosyncratic and individual. It’s a tall tale.”

But he also concedes these retro stadiums are better than the concrete behemoths that came before them. Citi Field may be a bit derivative, but Lamster still thinks it is better than what came before.

Asked to describe its predecessor, he says: “Yes I can describe Shea Stadium. Think of a toilet. Put seats in it. That’s Shea Stadium. Was it a nice place to watch a game? No. Is the new place a nice place to watch the game? Absolutely! It’s a much much nicer place to watch a game. It’s a really great place to watch a game.”

And being a nice and familiar place to watch a game is important for baseball. Even as television ratings have started to slide in recent decades, attendance numbers are strong — people enjoy going to the ballpark. And part of that is tied to tradition, that nostalgic experience of sitting in the stands, eating a hot dog and listening to organ music.

Baseball’s obsession with history and tradition helped drive the retro ballpark revolution. But, as an architecture critic Mark Lamster is ready for some team out there to embrace the future: “Why were we looking backwards when we designed these ballparks instead of looking towards new materials, and new ways of building, a new architecture?”

And if Camden Yards taught us anything, it’s this: when someone does come up with a great new way of building a ballpark, every team in the league is going to want one of their own.