In its heyday, Italy’s third-largest amphitheatre could hold over 20,000 bloodthirsty spectators, who would pour in to cheer on mock naval battles (yes, the stadium was occasionally flooded for fun), and indulge in a little schadenfreude as lions chased those captive Christians. Planned by Nero and completed by Vespasian (AD 69–79), the ancient stadium’s best-preserved remains lie under the main arena. Wander among the fallen columns and get your head around the complex mechanics involved in hoisting the caged wild beasts up to their waiting victims through the overhead ‘skylights’. In AD 305 seven Christian martyrs were thrown to the animals by the emperor Diocletian. They survived, only to be later beheaded. One of the seven was San Gennaro, the patron saint of Naples.