The Alamut Fortress( ÞáÚå ÇáãæÊ ) is a ruined medieval castle located in central Elburz mountains south of the Caspian Sea near Qazvin, built on top of a high rock reaching 2163 m above sea and on top of conglomerate hills adjacent to the Gazor Khan Village.

The castle lies on the peak known as 'Aluh Amut' or "Eagle's Nest". The first fortress was built in 840 A.D believed on ruins of a Sassanid (226-651 A.D) fortress. It was built in a way that had only one passable artificial entrance that wound its way around the cliff face (the only natural way was a steep gravel slope, too dangerous to use); thus making conquering the fortress was extremely difficult. The fort had an unusual system of water supply.
In 1090 the fortress was infiltrated and occupied by the powerful Hashashins, a faction of Ismailia Shia Muslims (known to the West as Assassins), and was then fabled for its gardens and libraries. The ruins of 23 other fortresses remain in the vicinity.
The fortress was destroyed on 1256 by Hulagu Khan as part of the Mongol offensive on southwest Asia.
In 2004, an earthquake further damaged the already crumbling walls of the fort. Reconstruction and archeological excavation is on progress, currently.
36° 26' 39.40" N 50° 35' 11.86" E