Qala'at al-Rabad, also known as Ajloun Castle, is a 12th-century Muslim castle situated in northwestern Jordan. It was built by the nephew of Salah al-Din (Saladin), Izz al-Din Usama, atop a hill in Ajloun to control the iron mines of Ajloun and to deter the Crusader advances from Jerusalem. The fortress offers panoramic views of the Jordan Valley and was a part of a defense system that included castles at Montreal (Shoubak), Kerak, and Belvoir. Echos of its strategic importance are evident in its placement and the remnants of its robust architecture. It is an outstanding example of Islamic architecture and military fortifications of the time. The castle was damaged by Mongol invasions, earthquakes, and by the forces of the Mamluk Sultan Baibars who restored it. Today, it is considered one of Jordan's most important and complete medieval examples of military architecture and tourists can explore its towers, arrow slits, and a fascinating museum detailing the history of the region and the castle itself.