Philadelphia City Hall. This ornate building was built between 1871 and 1901. The prototype is about 450 feet square by 548 feet high. There was an unofficial rule in Philadelphia, never broken until the 1980s, that no building may exceed this high (the top of William Penn's hat, to be exact, which topped the clock tower.) This model currently omits some of the statuary and other ornate features, including William Penn, in order to save polys.