The Venetian fortress KOULES located at the entrance of the Venetian harbor of Heraklion . It took its name from the Venetians founders who called it “Sea Fortress” (Castello a Mare or Rocca a Mare) but today has left known by its Turkish name Koules from Su Kulesi. It is one of the most famous monuments of the city and the symbol of Heraklion. The fortress Koules gazes proudly Cretan Sea reminding the glory of Venetian trench, is haunted by legends who want inside have tortured horribly Cretans rebels. In front of the castle shows the Lion of St. Mark , the symbol of Venice. The chronological period is estimated that created the period of Arab rule ( 9th-10th ) While there are clear references to the Byzantine period ( 10th-13th ) as Castellum Comunis.