The most remarkable buildings in the eastern Jordanian desert are the palaces built by the Umayyad caliphs in the 7th and 8th century. Most of the castles can be visited within one day in a loop from Amman via Azraq. The Desert Castles are examples of early Islamic art and architecture, built between 660 and 750. The majority of the castles lie on the ancient trade routes towards Medina and Kufa. The castles are partly rebuilt from earlier remains and partly new constructions. The function and use of the buildings are not totally clear, they may have been a fortress, a meeting place with the Bedouins, a caravenserai or leisure place.

The most popular castles can be visited in one day. Qasr Hallabat was originally constructed by the Roman emperor Caracalla, demolished and rebuilt by the Umayyads. In the castle 146 Greek inscriptions had been found, the site incorporates a mosque, a huge reservoir and several cisterns. Well preserved is Qasr Kharanah with its high walls and four corner towers. At first glance the construction is fortress, but it served most likely as a meeting place for the Umayyad caliphs.

The large black fortress Qasr Azraq, used by the Romans, Byzantines and Umayyads, gained its final building status by the Ayyubids, and in the 16th century the Ottomans stationed a garnison here. But the most popular occupant was Lawrence of Arabia, who at the beginning of the 20th century had here his headquarters during the Arab Revolt against the Ottoman Empire.

Qasr Amra is the most charming of the desert castles due to its fresco paintings. Built by caliph Walid I as a bathhouse, it consists of three different chambers and a hydraulic structure for the water supply. The most impressing are the early Islamic frescoe paintings with varied iconographic themes depicting hunting and bathing scenes, musicians and dancers. They represent the formative stage of Islamic art and therefore Qasr Amra is listed as an UNESCO World Heritage Site.