Karacahisar Castle
Karacahisar Castle, Karaca Hisar Castle or Karajahisar Castle (Turkish: Karacahisar Kalesi, Greek: Κάστρο Καρακαχίσαρ) is a ruined Byzantine castle on a plateau near the Porsuk River, southwest of Eskişehir, Turkey. It stands 1,010 metres (3,310 ft) above sea level, is surrounded by walls, and covers an area of 60,000 square meters.