Philadelphia City Hall, the seat of the administration of the American city of Philadelphia, located in Pennsylvania. The building is 167 m high, counting the height of the statue of the city's founder, William Penn, located at its top; it was the tallest skyscraper in the world from 1901 to 1908 , after which it remained the tallest in Pennsylvania until it was surpassed by the Gulf Tower in Pittsburgh in 1932; then it was the tallest building in Philadelphia, until the construction of Liberty Place (1984—1987) ended an informal gentleman's agreement that limited the height of buildings in the city. Today it is the 15th tallest building in the state. The town hall was the world's tallest masonry since the collapse of the Mole Antonelliana wing in Turin in 1953. The main materials used for its decoration are limestone, granite and marble. In 2007, the building was ranked 21st on the list of 150 most remarkable American buildings compiled by the American Institute of Architects.