The Colosseum is an oval amphitheatre in the centre of the city of Rome, Italy, just east of the Roman Forum. It is the largest ancient amphitheatre ever built, and is still the largest standing amphitheatre in the world today, despite its age. Construction began under the emperor Vespasian in 72 and was completed in 80 AD under his successor and heir, Titus. Further modifications were made during the reign of Domitian.