Scattered throughout the black basalt desert, east of Amman, the Desert Castles, a testament to the flourishing beginnings of Islamic-Arab civilization were at one time integrated agricultural or trading complexes, built mostly under the Umayyads (661-750 AD). Aside from being widely considered as the most spectacular and original monuments of early Islamic art, these complexes also served practical purposes as residences, caravanserais, and baths. Definitely worth visiting is Qasr al-Hallabat, Qasr Hammam as-Sarh, Qasr Amra en Qasr al-Harrana.