Dominating the headland at the western edge of town, this massive fortress is the one site everyone should give at least an hour to visit. Built under the Venetians (but by Cretans) from about 1573 to 1580, its huge walls, about 1,130m (3,700 ft.) in perimeter, were designed to deflect the worst cannon fire of its day. In the end, of course, the Turks simply went around it and took the town by avoiding the fort. There's a partially restored mosque inside as well as a Greek Orthodox chapel. It's in this vast area that most of the performances of the annual Rethymnon Renaissance Festival take place .