The Flavio Amphitheatre, which has the same name as the eternal city, it is the third largest after the Coliseum in Rome and the one of Maria Capua Vetere, in Capua.

Built in the time of Vespasian during the second half of the 1st century, with its 149,116 meters in length, the amphitheatre could hold up to 40 thousand people,  it had four main entrances and two secondary entrances and it had a complex theatrical structure composed of undergrounds, hallways, staircases, freight elevators for the lifting of the cages and a system which allowed the representation of the naumachiae (naval battles). In the north sector of the undergrounds you can see the chapel dedicated to Saint Januarius, erected in 1689. According to tradition, the Holy martyr might have been exposed in vain to the assault of the fair, before being decapitated in the church dedicated to him outside the walls of Pozzuoli.

Useful information: 
Open every day from 9:00 to 17:00  Full price tickets: €5