The Plaza on DeWitt was completed in 1966 as a residential apartment building at 260 E. Chestnut Street in the Streeterville neighborhood of Chicago. Originally called the DeWitt-Chestnut Apartment Building, and designed by Fazlur Khan while he was working for Skidmore, Owings & Merrill, it was the first building in the world to implement the tubular construction method later used for the World Trade Center. The 43-story tower accommodates 407 residences and is the tallest building in Chicago to be clad in travertine marble.