The Venetian Castle is considered unique in its kind in the Dodecanese. The castle is a 14th-15th century building, build by from the Querini family. It is located in the land of Astypalea, on the ancient Acropolis, avoiding the piracy that has been raging these centuries.
The castle stands out for its fortification. It housed more than 2000 people in an area of four acres. The castle pillar and the Serai Tower were the only strategic points of the fortress. The castle remained habitable until the 20th century, but due to the great earthquake of 1956, the last inhabitants abandoned it.
Inside, two churches with special architecture have been built: Agios Georgios (1790) and Virgin Mary of the Castle (1853).