The amphitheater, which was built under Emperor Augustus and extended under the Emperor Vespasian, is one of the main sights and at the same time the landmark of the city. It has a size of 133 meters x 105 meters, was about 23,000 people, making it one of the largest amphitheaters built by the Romans. The façade, which is in large parts up to the original height of 32.5 meters, is also august, according to a recent view.
Impressive, though not as big as the amphitheater, is the Sergierbogen built between 29 and 27 BC to commemorate the victory of Octavian in the battle of Actium. The Augustus Temple (2 BC to 14 AD) and the Archaeological Museum of Istria (AMI), with the Portorilina double gate, are also to be found in the main building of the museum.