The Colosseum is probably the most impressive building of the Roman empire. Originally known as the Flavian Amphitheater, it was the largest building of the era. Emperor Vespasian, founder of the Flavian Dynasty, started construction of the Colosseum in AD 72. The huge amphitheater was built on the site of an artificial lake, part of Nero's huge park in the center of Rome which also included the Golden House (Domus Aurea) and the nearby Colossus statue. This giant statue of Nero also gave the building its current name. The Colosseum could accommodate some 55,000 spectators who could enter the building through no less than 80 entrances. Above the ground are four storeys, the upper storey contained seating for lower classes and women. The lowest storey was preserved for prominent citizens. Emperors used the Colosseum to entertain the public with free games. Those games were a symbol of prestige and power and they were a way for an emperor to increase his popularity. The southern side of the Colosseum was felled by an earthquake in 847. Parts of the building - including the marble facade - were used for the construction of later monuments, including the St. Peter's Basilica.