Construction workers are celebrating atop the Austonian today, as they mark the topping out of the 56-story luxury condominiums, which at 683 feet is the tallest residential building in the United States outside of Chicago, Miami and New York City.

The Austonian became the city's tallest building in June.

Construction of the building at Congress Avenue and Second Street began on Sept. 17 two years ago. In May 2010, the Austin Women's Symphony League showcase will mark the opening of the Austonian, with residents moving into the building in June 2010.

The Austonian surpassed the 567-foot-tall 360 condominiums as the city's tallest building. By comparison, the San Antonio Tower of Americas is 622 feet in height; Dallas Reunion Tower is 560 feet; and, the Washington Monument is 555 feet, according to a news release.