Located about thirty kilometers northeast of Jerusalem in the western Jordan valley, the city of Jericho is built in a desert oasis, featuring an abundant water supply from the neighboring spring of Ain al-Sultan. Coupled with a warm, dry climate, the original settlement provided agricultural production as early as the sixth millennium BCE. The earliest site associated with this ancient city is Tell Ain al-Sultan, renowned for its unique, Neolithic stone tower, rising nearly eight meters in height, with a diameter of eight and a half meters. Approximately six hundred meters southwest of the Tell stands a hippodrome with a theatre and gymnasium. In addition, Jericho exhibits an assortment of sites from various historical moments, including a complex of palaces and forts built in mud brick with stone foundations by Herod the Great and his predecessors between the third and second centuries BC. Also among the prominent sites of the city are the eighth century Umayyad palace and bathhouse at Khirbat al-Mafjar; a chain of Byzantine Monasteries and a synagogue dating to the sixth century.