Pula
The most famous and important monument in Pula, and the starting and ending point of every sightseeing tour is the Amphitheater, which is better known as the Arena. This was once the venue for gladiator fights. It was raised in the 1st century AD during the reign of the Emperor Vespasian. It was built at the same time as the biggest and most well-known monument of its type - the Coliseum in Rome.
The ground plan is elliptical. The longer axis measures about 130 meters and the shorter one about 100 meters. Gladiator fights took place in the central flat area called the arena, while the spectators sat on the stone tiers or stood in the gallery. It is believed that the Amphitheater could seat about 20,000 spectators. Local limestone was used in its construction. In the Middle Ages, it was the site of knights' tournaments and fairs.
Today it is the venue for summer events such as the Film Festival, the Opera Season, the Equestrian Festival, and various concerts. It can seat about 5,000 spectators. The underground passages, once used by the gladiators, nowadays host a regular exhibition of viticulture and olive-growing in Istria in ancient times. The exhibits include reconstructions of equipment once used for producing olive oil and wine (mills, presses, vessels) and amphorae used for storing and transporting it.
Because of its size and geographical configuration, the Arena is situated outside the old city walls. The road that leads to the center was constructed during the reign of the Emperor Vespasian, after whom it was named - Via Flavia. Even today it's one of the city's main roads.
Source: http://www.pulainfo.hr/