Castles and Fortresses
Fortification in the Arab world took as many forms as the terrain demanded: the citadel on the urban mound, the desert palace on the caravan road, the mountain stronghold above a pass, the coastal tower watching for raiders.
The Citadel of Aleppo sits on a hill occupied for thousands of years and remains one of the largest and oldest castles in the world. Cairo's Citadel of Salah al-Din governed Egypt for seven centuries. Erbil's citadel rises on a tell that may have been inhabited continuously for six thousand years.
The Crusader castles of the Levant — Crac des Chevaliers, Qal'at Salah El-Din, Shawbak, Kerak — were built for a frontier and later rebuilt by the Ayyubids and Mamluks, so most of them record two military traditions in the same walls.
Oman alone has more than five hundred forts and towers, from Bahla and its World Heritage oasis walls to Nizwa's great round tower. In the Maghreb the ribat at Monastir and Sousse combined garrison and religious retreat, and across the Sahara the ksour fortified entire villages behind a single gate.