The Roman Colosseum, originally named Flavian Amphitheatre, is the world’s largest amphitheater ever built. Completed in 80 AD, it is constructed out of travertine, tuff, and brick-faced concrete.
The average audience was approximately 65,000 but capacity ranged from 50,000 to 80,000 spectators. It was used for contests among the gladiators, and unfortunately, around 9,000 animals were killed during the inaugural games.
The Roman Colosseum is an elliptical building constructed 615 feet (189 m) long and 510 feet (156 m) wide. The base encompasses 6 acres (24,000 sq m). The outer wall reaches a height of 157 feet (48 m). The central arena is 287 feet (87 m) long and 180 feet (55 m) wide. The outer wall is believed to have needed 3,531,467 cubic feet (100,000 cu m) of travertine stone.