Philadelphia is home to many skyscrapers designed by well-known architects from around the world. Among these are the twin towers of Commerce Square, which were designed by the renowned firm of I.M. Pei & Partners. The 565-foot-tall One Commerce Square and Two Commerce Square towers are still prominent on the Philadelphia skyline to this day, and they take up an entire city block at 2001 Market Street and 2005 Market Street in Center City. Both of the 41-story structures are framed in steel, and each is topped with a decorative diamond on the east and west faces. Maguire Thomas Partners was the developer of the towers at the time of the completion of One Commerce Square in 1987 and five years when Two Commerce Square was completed, which was also the time when the developers decided to split their partnership.
The towers are connected by a low-rise structure filled with retail and decorated in the same stone and glass that is used for the skyscrapers. In the center of the complex is a public plaza accessible from the south side. Each tower steps up with several setbacks to a diamond-topped crown in a stone and glass design that keeps the 1980s postmodernist style apparent.
The parking lot that formerly occupied the site was cleared on June 3, 1985, with bulldozers on site. Excavation for One Commerce Square was underway in July, and a deep pit was dug out later in the year. On June 6, 1986, the tower’s crown had topped out, with the east diamond being the last piece of the steel structure. Not counting the antenna atop the PSFS Building, One Commerce Square became Philadelphia’s first skyscraper to break the “gentlemen’s agreement” by surpassing the 548-foot-tall main tower of City Hall, almost a year ahead of the better-known, 945-foot-tall tower of One Liberty Place. One Commerce Square opened in October 1987. The second tower was finished in 1992 after being on hold after searching for an anchor tenant to construct the tower.