The jury of the Emporis Skyscraper Award named Aqua, an 81-story residential and hotel tower in Chicago, the winner of its 2009 Skyscraper of the Year. The award, now celebrating its tenth year, is given annually to a building at least 100 meters tall and completed within the award year. The second place winner is O14 in Dubai and third place went to The Met in Bangkok. All winners were selected from 305 eligible buildings completed worldwide in 2009.

Designed by Jeanne Gang of Studio Gang Architects, Aqua intersperses undulating balconies with flat glassy planes to create a wavy facade in keeping with its nautical theme. Because each balcony’s perimeter varies slightly from the one below, contractors James McHugh Construction Co. employed a flexible mold in coordination with GPS. Gang says the effect has been compared to a rippled curtain or the striated limestone formations common to the Great Lakes region.

The developer Magellan Development Group LLC has applied for LEED certification. Viracon supplied the low-E coated insulating glass in all windows. Frit patterned glass was also used in the railings to help prevent bird strikes.

Aqua is the third-tallest building in the world designed by a woman – surpassed only by the two Emirates Towers in Dubai – and is currently the 40th tallest building in the United States. Aqua has a height of 249.7 meters (819.34 feet) measured from its main entrance.

According to the announcement, embers of the jury praised Aqua for having a fascinating shape and appearance that change dramatically depending on the perspective. It was also cited as a “brilliant technical achievement” for the precision of its construction, and lauded as an application of green design innovations to an extremely large building project.