Al Kerak, Jordan
Built in 1161 by the Crusaders, Kerak is a perfect example of mediaeval castle design. The castle is a dark maze of stone-vaulted halls and passageways. Its most famous occupant was Reynald de Chatillon, who had a reputation for treachery and brutality.
Reynald de Chatillon was not your perfect example of a Chivalric Knight. He broke all treaties and regularly robbed merchant caravans and pilgrims, raided ports, and even went so far as to attack Hejaz, the homeland of Islam, and threaten Mecca. Unsurprisingly, Saladin, the ruler of Syria and Egypt, was swift to respond. He burned the town of Kerak to the ground and almost conquered the castle itself.
After Reynald robbed a large caravan in 1177, Saladin attacked the Crusader Kingdom again, and finally defeated them at the Battle of Hattin. Whilst most of the captives were spared, Saladin executed Reynald himself. The defenders of the Kerak Castle were able to hold out under siege for eight months before surrendering and being allowed to walk free.