Although the Venetians called it Castello a Mare ( Castle on the Sea), the Turkish name prevailed: Koules, from Su Kulesi (Water Castle). Its purpose was to protect the harbor of Heraklion and guard the bay of Ammoudara from any threat, along with the Palaiokastro Castle. Koules has been dominating the entrance of Heraklion harbour for about five centuries and is considered to be the hallmark of the modern city of Heraklion.
You can visit Koules daily (except Mondays) from 8:30 to 15:00 during the winter months, while in the summer, it remains open until 19:00.
After visiting the Fortress, make your way to Heraklion lighthouse and take a look at street art on the walls of the pier.
