Writing in The New Yorker earlier this year, Paul Goldberger offered his take on the newly opened Aqua, the undulating 82-story skyscraper at 225 North Columbus Drive. The Pulitzer Prize–winning critic loved the building—“ingenious”—and grouped its designer, Jeanne Gang of Chicago’s Studio Gang, among the city’s most illustrious architects, among them Louis Sullivan, John Root, and Ludwig Mies van der Rohe. Recently, Gang discussed a few of the behind-the-scenes details that contributed to Aqua’s success.

Partial Eclipse
Studies of the sun’s position throughout the year determined the balconies’ placements. “In wintertime, when the sun is low, you get the sun coming in when you want it,” says Gang. In the summer, when the sun is higher, the balconies act as shades that keep Aqua cool.

Reflecting Pools
The weave of balconies delineated areas of unshaded glass—Gang calls them “pools”—that were both beautiful and problematic. “After we had created this landscape, we realized there were going to be areas that didn’t have sun screens,” Gang says. To solve that problem, builders used a more reflective glazed glass in those areas to help repel the sun’s heat.

View the gallery below for info on specific aspects of the building.

Sight Unseen
Recognizing that Aqua would stand within a cluster of tall buildings, Studio Gang calculated various “lines of desire” that would provide residents unexpected views of the cityscape from their bumped-out balconies.

Gust Busters
The balconies’ staggered placements prevent the wind from picking up speed as it encounters the building, which means that Aqua’s residents can enjoy their balconies without being buffeted.

Hood Winks
Gang seems especially delighted that Aqua has become, in her words, a “vertical community” where residents can “inhabit the façade” and even give a shout-out to their neighbors.

Sweet Home
Neighborly spirit spills over to the 80,000-square-foot green roof (on the second floor), where condo owners and apartment dwellers democratically mingle. “They all share this amazing roof garden,” says Gang. “It’s helping make a community out of Aqua.”

On the Fly
To pour the concrete floors, builders used “flying formworks”—basically a big platform hanging off the side of the building (rather than resting on the recently installed floors below) that allowed each floor to be poured in three days rather than the usual week.

The Plot Thickens
After Studio Gang digitally plotted each of Aqua’s distinctive contours, builders used that information and GPS-like coordinates to precisely pour the 82 differently shaped concrete floors.

Rock of Ages
Gang and her colleagues drew inspiration for Aqua’s furrowed façade from the striated limestone formations that rise up along the shores of the Great Lakes.

Photograph: Steve Hall/ © Hedrich Blessing