The Kasbah of the Udayas was added to the UNESCO World Heritage Tentative List on July 20, 2006 in the Cultural category.
A kasbah (Arabic: القصبة al-qaṣbah) or qassabah is a type of medina, Islamic city, or fortress (citadel). It was a place for the local leader to live and a defense when a city was under attack. A kasbah has high walls, usually without windows. Sometimes, they were built on hilltops so that they could be more easily defended. Some were placed near the entrance to harbors.
The Kasbah of the Udayas is a kasbah in Rabat, Morocco located at the mouth of the Bou Regreg river opposite of Salé. It was built during the reign of the Almohads. When the Almohads had captured Rabat and destroyed the kasbah of the Almoravids in the town, they began reconstructing it in AH 544 / AD 1150. They added a palace and a mosque and named it al-Mahdiyya, after their ancestor al-Mahdi Ibn Tumart. After the death of Yaqub al-Mansur (AH 595 / AD 1199) the kasbah was deserted. The Almohads brought significant changes to the Rabat area, including the destruction and rebuilding of the Kasbah of the Udayas and turning Chellah into a royal necropolis.