Shelbourne Development Group, Inc., filed with the city of Chicago for design approval to build "The Chicago Spire," a 2,000-foot-tall tower at the mouth of the Chicago River that the company claims will be the world’s tallest residential structure. The plan, revised after the company acquired the property in July 2006, includes several improvements, according to Shelbourne, that will enhance the building’s integration with the riverfront and minimize traffic flow through the neighborhood.

"The sculptural idea of an extremely slender building that twists as it rises has been retained," said Santiago Calatrava, who is both the lead architect and engineer for the project. "But I believe the design is more mature than it was initially, and the relationship between the building and the city is better."

Current plans call for the property to encompass 3 million square feet. A broadcast antenna, hotel, and retail space were cut from the initial design. The number of floors was increased from 124 to 160; the number of residences was increased to 1,300. The tower’s lobby will feature a 56-foot-tall ceiling and glass walls, allowing for an unobstructed view through the base on all sides.

If the city approves the design changes, Shelbourne expects to break ground in 2007. More information about The Chicago Spire is available online at