Vespasian's Amphitheater (Arena) is the biggest and one of the best-preserved examples of Antique architecture in Croatia.
No written sources exist about the construction of the most splendid structure in Pula's history.
Its origin is dated back to the reign of Emperor Augustus. In terms of stylistic features the wall with large semicircular openings on two storeys can be dated back to the mid-1st century, i.e. the reign of Emperor Claudius. The last stage of construction of the third storey and completion of the amphitheatre is assumed to have taken place during the rule of Emperor Titus Flavius Vespasian around the year 80 A.D.

This geometrically designed structure is elliptical in appearance. It is 133 meters long, 105 meters wide with the height reaching up to 32.5 meters on the side facing the sea. The eastern part of the structure has only two storeys and is built on a natural elevation for reasons of simplicity and stability. 

In the central part of the amphitheatre there is a 67.90 x 41.60-meter arena which was separated from the auditorium by a 1.16-meter wide canal covered with plates. Access to the arena was provided by two main entrances placed in the direction of its longer axis and as well as by a number of side entrances.

The auditorium was located above the arena and spread like an ellipsoidal funnel in concentric rows of stone seats arranged in terraces. There were stairs leading from one storey to another. The auditorium was covered by a canvas tent and could seat 20,000. The outer wall is composed of the main substructure, two storeys of arcades with 72 arches and the topmost storey with 64 square windows. At the top there is a wall crown made from stone blocks and horizontal grooved stone beams. In the four towers attached to the outer faÁade there were double stairs that provided access to the upper storeys. Below the arena, in the direction of its longer axis, there was a room whose ceiling was supported by columns and pilasters which served for storage of props. Below the arena there was a system of sewers for collecting water that was then drained into the sea. 

Fall of the Roman Empire, obstruction of progress and decline of civilization on the whole led to mass destruction of Antique architecture: iron bars were removed and stone blocks were used to construct other houses and buildings. Luckily, the Arena remained preserved for the generations to come. It is nowadays a popular venue for different cultural events.