The colosseum (their spelling) would have held 50,000 to 70,000
spectators, seated according to class. The lower levels were for
emperors and the upper class. One of the most popular events were the
gladiator games.
Exterior.
Arch of Constantine, which is next to it.
Interior.
The lower level beneath the arena held storerooms, passageways,
dressing rooms, etc. Animals were kept here before the shows.