The Fortress of Agios Georgios is located at the village Peratata on a 300 m altitude and was probably constructed during the 12th century AD by Byzantine Emperors. It’s about 16.000 m2 and its surrounding walls are approximately 600 m long. Inside the walls there were public and private buildings, churches, food and ammunition warehouses, barracks, hospitals, prisons and water tanks. Visitors will also see the remnants of the catholic church of Agios Nikolaos and a tunnel that led from the castle to the lagoon of Koutavos and it was used in case of emergency exit. This castle was actually the capital of the island till 1757, when Argostoli became the new capital, but it was heavily damaged during the earthquakes of 1636, 1637 and 1953.