The Colosseum is an ancient Roman stadium designed to seat fifty thousand spectators for events such as gladiator and animal fights. Romans even held mock sea battles here, and were able to flood the arena for such events. Built between 72 and 80 C.E., it was the largest Roman amphitheater and was originally known as the Flavian Amphitheater. The original central arena was nearly thirty-thousand square feet and the whole structure is more than six hundred feet in diameter. The façade of the building was made of three levels of eighty-arch arcades (a row of arches), plus an attic level, and supported six tiers of seats. Under the seats, barrel-vaulted corridors allowed for the passage of athletes and animals. Each of the three arcade levels is decorated according to a different architectural order, which become more complex as the building rises. The first floor utilizes the simple Tuscan order, while the second and third floor incorporate elements from the Ionic and Corinthian order, respectively. The exterior had been faced with travertine, but this relatively expensive material has since been looted.