Mamure Castle sits 7 km southeast of Anamur town, right at the edge of the sea — the outer walls drop almost directly into the Mediterranean. The fortress was first built by the Romans around the 3rd century AD to guard this stretch of coast, then substantially expanded by the Byzantines and later the Karamanid Turks in the 13th century. The result is a layered structure covering roughly four hectares, with three distinct courtyards, a moat fed from a nearby stream, and 39 towers that remain largely intact.
The interior rewards a slow walk. The 13th-century mosque in the inner courtyard is in reasonable condition, and you can scramble up onto sections of the outer wall for views along the coast toward the cape. The site is not heavily managed — there are no guided tours, no gift shops — just the castle and the sound of the sea. Admission is cheap and it rarely gets crowded, even in summer.