Dive into the ancient history of the Colosseum. The Colosseum, also known as the Flavian Amphitheater, is an oval magnificent architecture in the center of Rome. Built of travertine, tuff and brick-faced concrete. It is the largest construction ever build in ancient Rome. It is situated just east of the Roman Forum. Emperor Vespasian began the construction in 72 AD and was completed in 80 AD by its successor Titus.