Only Rome's Colosseum and Capua's arena would dwarf this amphitheater, built for gymnastic competitions, choreographed sacrificial rites, and games involving hunts, fights, battles, and wild animals. Though four arches are all that remain of the arena's outer arcade, the main structure is complete and dates from AD 30. In summer, you can join up to 16,000 people packing the stands for spectacular opera productions. Even those not crazy about opera can sit in the stands and enjoy Italians enjoying themselves—including, at times, singing along with their favorite hits. The opera's the main thing here: when there is no opera performance, you can still enter the interior, but the arena is less impressive inside than the Colosseum or other Roman amphitheaters.