Kuh Qaen Castle

Kuh Qaen castle or Ghal'eh-Kuh of Qa'en, also known as Husayn Qa'ini Castle (قلعه جسین قائنی), is a historical castle located in Qaen County in South Khorasan Province, The fortress dates back to the Ismailis of the Alamut Period. It was one of their most important strongholds in Quhistan.