Roman audiences watched a variety of athletic events, blood sports, and spectacles, including animal hunts, fights to the death between gladiators or between gladiators and wild animals, performances of trained animals and acrobats, and even mock sea battles, for which the arena would be flooded. The opening performances in 80 CE lasted 100 days, during which time it was claimed that 9,000 wild animals and 2,000 gladiators died for the amusement of the spectators.
The amphitheater is a remarkable piece of planning, with easy access, perfect sight lines for everyone, and effective crowd control. Stadiums today are still based on this efficient plan. Each level of seats was laid over barrel-vaulted access corridors and entrance tunnels. The intersection of the barrel-vaulted entrance tunnels and the ring corridors created groin vaults. The walls on the top level of the arena supported a huge awning that could shade the seating areas. The curving outer wall of the Colosseum consists of three levels of arcades surmounted by a wall-like attic story. Each arc is framed by engaged columns. Entablature-like friezes mark the divisions between levels. Each level also uses a different architectural order, increasing in complexity from bottom to top: the plain Tuscan order on the ground level, Ionic on the second level, Corinthian on the third, and Corinthian pilasters on the fourth. The attic story is broken by small, square windows, which originally alternated with gilded-bronze shield-shaped ornaments called caratouches, supported on brackets that are still in place.