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.
This site was added to the UNESCO World Heritage Tentative List on July 20, 2006 in the Cultural category.
Rabat (Arabic الرباط; Amazigh ⵕⴱⴰⵟ, transliterated ar-Rabāṭ or ar-Ribāṭ or Rbat, literally "Fortified Place"; French Ville de Rabat; ESpanish Ciudad de Rabat), is the capital and third largest city of the Kingdom of Morocco with a population of approximately 650,000 (2010). It is also the capital of the Rabat-Salé-Zemmour-Zaer region.
The city is located on the Atlantic Ocean at the mouth of the river Bou Regreg. On the facing shore of the river lies Salé, the city's main commuter town. Together with Temara the cities account for a combined metropolitan population of 1.8 million. Silting problems have diminished the Rabat's role as a port; however, Rabat and Salé still maintain important textile, food processing and construction industries. In addition, tourism and the presence of all foreign embassies in Morocco serve to make Rabat one of the most important cities in the country. Controversy surrounds sweatshop labour by major multinational corporations in the area (see Salé).