Ruins of a fortress stand on a hill southwest of Papadianika. There are historical references to a fortress and settlement called Asopos that belonged to the Despotate of the Morea. After 1463, it was occupied consecutively by the Venetians and Turks.
It was used by the local population as a place of refuge during raids by pirates and in Turkish attacks, and was much admired, particularly by naturalists travelling in the area.
The view is unique, taking in the entire Gulf of Laconia from Gytheio to the island of Kythera.
Two kilometres along the road from Papadianika to Demonia, the hill is easily recognisable. A sign at the side of the road indicates the beginning of a relatively short and not very arduous walk (30-60 minutes) to the site.