Chicago’s famous for its architecture. But in the 1980s and early ’90s, it seemed the city was coasting on its reputation. Critics wondered if architecture was dead. Now, though, architects are playing with new tools, and a new focus on issues like the environment and urban density. These innovations could change how our buildings look and how we live.

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To understand where Chicago got its reputation in the first place, we’ve got to go back a century to when Chicago was one of the fastest growing cities in the world.

We’ll enter a courtyard encased in marble so white, it almost hurts to look at.

TOUR: We’re standing in the atrium of the Rookery Building. This is a building that’s at the beginning of the really large tall buildings.

Bob Bruegmann points up through the glass at white glazed terra cotta. It hides the metal frame on the courtyard side. That frame was an important step toward the tall buildings of today, along with inventions like safety elevators and good fireproofing.

BRUEGMANN: They came together in Chicago in the way that created this kind of skyscraper city that was really the shock city of the 19th century. It was the city where people came from all over the world trying to see what the future might look like.

Bruegmann’s a professor of art history, architecture and urban planning at the University of Illinois at Chicago.

He says that period, known as the Chicago School, is still world famous.

BRUEGMANN: The most important achievement was that it created an entirely new kind of urbanism, this landscape of cliffs of masonry on either side of the street, the idea of a downtown being primarily about office buildings.

That period was followed by the Art Deco period of the 1920s, and gems like the Board of Trade. And the steel boxes of the ’50s and ’60s. Think Mies van der Rohe, who designed the Illinois Institute of Technology campus. It’s like a modernist picture book, and people still come from all over to see it. But then came all the terrible imitators and some truly ugly post-modernist buildings.

BEY: It’s gone through some periods, particularly in the 90s, where it felt it was dead. When I was at the Sun Times, the story line of the day between the two critics in town was has Chicago lost its groove, because we were building so many of these painted concrete boxes.

Lee Bey’s a former Sun-Times architecture critic. Now he spends a lot of time on planning as head of the Chicago Central Area Committee, and writes an architecture blog.

BEY: I think we’re just at the beginning of something that I think is going to be really exciting as buildings are designed not just for the purposes of aesthetics, but really to respond to their environment.

Take the Modern Wing at the Art Institute that connects you to the street, instead of closing you off from it, and the Spertus Institute that twists the traditional glass curtain wall into origami.

At IIT, architect Rem Koolhaas built a student center under the EL and wrapped a huge tube around the tracks, to muffle the noise.

ROBERTSON: One of the Chicago trademarks is an attention to the materiality and an experimentation with it. I think that will be, of course, one of the calling cards of new architecture in Chicago.

Architecture Dean Donna Robertson points to Helmut Jahn’s student dorms, wrapped in corrugated stainless steel. Robertson says the building comes right out to the sidewalk to reinforce vibrant street life.

ROBERTSON:  The way in which architecture engages to the city may be one of the lasting legacies of these buildings or others that are coming along right now. I think we are all very highly conscious of how architecture should contribute to civic life.

Critic Lee Bey: 

BEY: We’re going to see things and shapes and forms and materials that I think we’ve never seen before.

Like Aqua, a new residential tower going up just south of the Chicago River. To picture what it looks like, think of scalloped balconies that ripple across the side of a building like waves.

Jeanne Gang is the founder of Studio Gang Architects, the designer of Aqua.

GANG: See how it??s kind of buried in between all these other buildings? So we thought if we just bump out this edge of the building here, we might be able to see around the corner, so it’s really a three-dimensional game.

The undulating balconies allow views of landmarks like Navy Pier and the Bean. Gang uses different types of glass, too, so areas that get a lot of sun are more reflective. Now her firm plans to build a high-rise in Hyde Park and angle it to let in light in the winter, and block it in the summer.

Gang says new tools and materials are letting architects dream in different shapes and forms.

GANG: Things you couldn’t do before maybe because you were forced into repetition from construction, that’s where we’ve really been liberated. I love Marina towers, but they are the way they are because they needed to be repetitious. We can break away from that.

FELSEN: Imagine a city in which you can buy an apartment or a house in walking distance to the grocery store, to the drycleaner, to the park, a walkable connection to the train.

Architects Martin Felsen and Sarah Dunn founded Urban Lab, an architecture firm concerned with sustainable design.

The couple says greater density is necessary, clustered near mass transit, because our sprawling cities and suburbs aren’t sustainable the way they are now.

FELSEN: If the past was defined by economic opportunities defining how Chicago was shaped, I think the next 30 years or so will be defined by crises. So the first is the economic crisis, second will be the energy crisis when it comes back, and the third we think will be what we call water crisis.

Urban Lab wants to build things like bike paths and prairies to add to the city’s green space. These eco-boulevards would filter storm water and waste and send it back to Lake Michigan to keep recharging water levels.

These are just some of the innovations architects are dreaming up across the region.

Bob Somol, the director of UIC’s School of Architecture, says we’re justifiably proud of our architectural heritage. But there’s a danger of complacency.

SOMOL: The great asset of Chicago, which is just do it, make it happen, which is very liberating in some ways, also can happen in a moment that precludes reflection and ideas. And so just doing it can also mean doing it in the lowest common denominator or the most clichéd way.

The recession is limiting big new projects right now. But Somol doesn’t think that’s necessarily bad.

SOMOL: Economic crises are always good for schools, and they tend to cleanse a lot of things that were happening in practice that maybe shouldn’t have been happening if times were leaner. So it’s a little bit like a forest fire that occasionally you need to have some loss in order to grow again and develop new possibilities.

He says Chicago has a strong streak of pragmatism. And that could lead to cutting corners and limit how much we push more extreme ideas. Or it could be a great source of invention that revives our architectural reputation for another generation.