The Colosseum is an elliptical amphitheatre in the center of the city of Rome, Italy, just east of the Roman Forum. It is the largest ancient amphitheatre ever built, and is the largest standing amphitheatre in the world. Construction began under the Emperor Vespasian (r. 69–79 AD) in 72 and was completed in AD 80 under his successor and heir, Titus (r. 79–81).

Source: Wikipedia