Monolithos is a village on the island of Rhodes, belonging to the municipal unit of Attavyros. It is located 10 km south-east of Apolakkia and 30 km from Prasonisi. Outside the village is the medieval Castle, built on top of a 100m rock.
This castle was built in 1480 by the Knights of Saint John to protect the island from attacks. In fact, this castle was never conquered. The Castle of Monolithos is widely ruined today but it offers great views of the sea and the two islets opposite to it. Inside the Castle, there is a small chapel dedicated to Agios Panteleimon (Saint Pantaleon). Access to the castle is by a staircase cut into the rock.