Rudkhan Castle

Rudkhan Castle; also Roodkhan Castle, is a brick and stone medieval fortress in Iran that was built by the Gilaks to defend against the Arab invaders during the Muslim conquest of Persia. With the fall of the Sasanian Empire, this area became a defensive position against the Arabs in the then-newly established Tabarestan.

Located 25 km southwest of Fuman city north of Iran in Gilan province, it is a military complex which was constructed during the Sasanian era, and later rebuilt in 1096 by the Nizari Isma'ilis for use by the Assassins. The castle is built on two tips of a mount, with an area of 2.6 hectares. Its architects made use of natural mountainous features in the construction of the fort.

Source: Wikipedia