The Colosseum, an iconic symbol of ancient Rome, was built by the ancient Roman civilization. Construction of the Colosseum began under Emperor Vespasian around 70 AD and was completed in 80 AD under his successor, Titus. This monumental structure could hold tens of thousands of spectators who came to watch gladiatorial contests and public spectacles, such as animal hunts and mock naval battles. The Colosseum's architectural design was innovative for its time, featuring a complex system of vaults and arches that allowed for large crowds. Today, it stands as a UNESCO World Heritage Site, representing the grandeur of Roman engineering and culture.