Italy, Rome, Colosseum Amphitheatre (00:04:02)

The Colosseum is built of travertine limestone, tuff (volcanic rock), and brick-faced concrete. It could hold an estimated 50,000 to 80,000 spectators at various points in its history,^[4][5] having an average audience of some 65,000; it was used for gladiatorial contests and public spectacles including animal hunts, executions, re-enactments of famous battles, and dramas based on Roman mythology, and briefly mock sea battles. The building ceased to be used for entertainment in the early medieval era. It was later reused for such purposes as housing, workshops, quarters for a religious order, a fortress, a quarry, and a Christian shrine.