Initially, the Venetians called their fortress “Rocca al mare”, which is translated from Italian as “Rock by the sea”. The fortress received the name “Kules” during the Turkish rule, the Turks called it “Su Kulesi”, translated from Turkish as “Water Tower”. In addition to the fact that the Koules fort was a source of water, it was also used by the Turks as a prison, for imprisoning Cretan rebels here.

The Koules fortress consists of two floors. On the first floor there are 26 rooms, which contained food warehouses and ammunition depots, as well as prison cells.

Over the years of its existence, the Koules fortress was repeatedly attacked and besieged for a long time, and in the 17th century it witnessed dramatic events when, after an attack by the Turks, the Venetians lost one of the most powerful fortifications in Crete and throughout the eastern Mediterranean.