So you think Chicago is a tale of two cities? The gulf between its booming downtown and its violence-plagued neighborhoods is nothing compared to the gaps that a visitor witnesses in Detroit.

Along Woodward Avenue, Detroit's main drag, a new streetcar line will start running in a few weeks. Construction crews are turning old high-rises into micro-lofts and building a sports arena that will open next fall. On the site of the old Hudson's department store that was imploded in 1998, the Quicken Loans magnate and real estate developer Dan Gilbert has proposed a skyscraper that would be taller than the glass-sheathed Renaissance Center, currently the city's tallest building.

Yet outside the resurgent downtown core, it's another story. Elegant old neighborhoods like Indian Village, a national historic district, quickly give way to expanses of empty lots that bring to mind Chicago's impoverished Englewood area. Detroit has roughly 25 square miles of vacant land — enough to fill the entire island of Manhattan and then some. Thousands of blighted homes have been torn down.

As Chicagoans know from the innovations that followed the Great Fire of 1871, necessity (or is it desperation?) often serves as the mother of invention. Accordingly, Detroit is evolving new ideas for how to revive its stricken neighborhoods. Here's what they boil down to: Turn emptiness into opportunity. Make a new kind of city — still urban, but more spread out. And while you're at it, avoid the gentrification that typically goes hand-in-hand with redevelopment.

"What's going to distinguish Detroit's recovery from any other comeback city is its ability to be an equitable recovery," Maurice Cox, Detroit's planning director, told me.

I interviewed Cox last month during a program at the convention of the Association of Collegiate Schools of Architecture. Cox, who grew up in Brooklyn, once was mayor of Charlottesville, Va. Detroit Mayor Mike Duggan hired him in 2015. The two have made Detroit a must-see laboratory for the reimagining and remaking of a shrinking city. Yet the hill they're climbing is incredibly steep.

Battered by plant closings, racial tensions and the ongoing flight of residents both white and black, Detroit's population has plummeted from a peak of more than 1.8 million in 1950 to fewer than 680,000 in 2015. It is no longer one of the nation's 20 most populous cities. Nor is it the manufacturing hub it once was. The once-mighty Motor City is down to two vehicle assembly plants, one operated by General Motors, the other by Chrysler.

Ryan Garza / Detroit Free Press The fenced area will be developed to expand Milliken State Park in Detroit. The fenced area will be developed to expand Milliken State Park in Detroit. (Ryan Garza / Detroit Free Press) (Ryan Garza / Detroit Free Press)

With thousands of good-paying jobs gone, skeptics question whether the city will ever regain the economic wherewithal to ensure that its renaissance extends beyond its downtown core.

"It's problematic to imagine that, just because you've got an attractive neighborhood running up Woodward, it's going to serve the needs of a poor kid living five miles away, let alone five blocks away," said Northwestern University historian Kevin Boyle, who grew up in Detroit and has written extensively about the city.

Detroit is nevertheless making strides — not with big plans, but with small steps. In 2016, two years after it emerged from its landmark bankruptcy, it finished a multiyear effort to install 65,000 streetlights and eliminate fear-inducing zones of darkness.

"You can't ask people to plan, which is inherently aspirational and visionary, if you can't provide basic services," Cox said.

The city is also going back to basics downtown, embracing anew the idea that city streets should accommodate transit, not just cars.

Bright red, articulated QLine streetcars will start operations May 12. The sleek QLine, which seems sure to be extended beyond its initial length of 3.3 miles, could not be more different from Detroit's People Mover, the elevated and automated light rail that opened in 1987 and is raised on expresswaylike stilts. Unlike the People Mover, which encircles downtown, the street-level QLine extends into neighborhoods, encouraging residents to leave their cars behind.

"We are trying to establish the public's trust in transit that's something accessible to all, not just something for the poor," said Cox.

One of the neighborhoods along the QLine — Brush Park, which sits between downtown and Detroit's midtown business district — shows the impact such steps can make.

Once boasting 19th century Victorian mansions, Brush Park succumbed to decline as its residents moved farther away from downtown and its grand houses were split into apartments and later demolished. Today, a large swath of the neighborhood is almost entirely vacant, its plots covered with grass even though downtown skyscrapers and stadiums, and the under-construction Little Caesars Arena, are close by.

Yet spurred on in part by the QLine, Quicken Loans' Gilbert is moving ahead with an innovative 410-unit residential complex in the heart of Brush Park. The complex, called City Modern, will incorporate four surviving Victorian mansions within a street-friendly cluster of contemporary houses and apartments. Chicago's Studio Dwell architects designed the townhouses, which promise to effectively mix modern design with traditional urbanism — a blend Cox encourages. City Modern is Detroit's largest new residential development.

"Detroit has switched from the city of demolition to the city of planning to the city of building," said Melissa Dittmer, an Illinois Institute of Technology graduate who is director of architecture and design at Bedrock Real Estate Services, the real estate and development company for Gilbert's Detroit properties.

An even more powerful symbol of Detroit's revival could emerge if Gilbert realizes his recently unveiled proposal for an eye-grabbing skyscraper on the old Hudson's department store site.

The design, by New York's SHoP architects, calls for a 52-story residential tower atop a swoopy nine-story podium that would house shops and enable other uses. While the plan is not aesthetically persuasive — the podium is overcooked; the tower, undercooked — it nonetheless sends a strong message: Downtown Detroit has reached the point where a showcase residential tower is not seen as a laughingstock.

At 734 feet, this one would nudge a little higher than the 727-foot Renaissance Center, which is now home to General Motors' headquarters.

It's time for Detroit to go "vertical," Gilbert has said.

Once you drive the freeways outside downtown, however, it's hard to maintain such optimism. One neighborhood I visited, Brightmoor, about 13 miles northwest of downtown, had numerous blocks in which there were more empty lots than houses. Many of the remaining houses had holes in their walls and roofs. Uprooted trees lay across yards. The sidewalks were empty. And the prospects seemed as dim, or dimmer, than they do in the troubled neighborhoods on Chicago's South and West sides.