Although it's tiny, the Paphos Fort is one of the most recognisable sights in Paphos. Built in 1592 by the Ottomans, it is sited over an earlier medieval castle built by the Lusignans, which in turn was built over an earlier Byzantine fort. You enter by crossing a tiny bridge across a moat.
Its prime position, overlooking the harbor, made it an excellent line of defense for the town. This is the number one spot in town for sweeping views across the Mediterranean.
Climb to the roof for great panoramas of the harbor area and the sea beyond. There are also ruins of another fort on the breakwater, but these consist only of two lumps of rock.