52 Roman Aechitectuee. In the foremost rank is the Flavian amphitheatre, known as the Colosseum, which was begun by Vespasian and finished by Titus. It was the largest structure of its kind, and is fairly well preserved. It covers about five acres of ground, and could contain 87,000 persons. It is 620 feet long by 513 broad. The exterior is about 160 feet in height, and consists of three orders of columns — Doric, Ionic, and 27 —The Arch of Constantino. Corinthian — with a story of Corinthian pilasters above them all. There are arches between the columns, forming open galleries throughout the building. Four tiers of seats inside correspond with the four outside stories. The building was covered in by a temporary roof or awning, called the velarium. The Triumphal Arch of Titus, at Rome (a.d. 70), is well preserved, and is remarkable for
