Centre Square is an office complex in Center City, Philadelphia, Pennsylvania, United States. The complex consists of two concrete high-rise towers: the 417 feet (127 m) Centre Square I (also known as Centre Square East) and the 490 feet (150 m) Centre Square II (Centre Square West) — respectively, the 24th- and 15th-tallest buildings in Philadelphia. Designed by Vincent Kling & Associates in the 1960s, Centre Square opened in 1973. The complex is credited with shifting Philadelphia's downtown office district from South Broad Street to West Market Street. A tenant since 1975, management consulting firm Towers Perrin is Centre Square's largest tenant.