UNDOF (the United Nations Disengagement Observer Force) was established in 1974 to supervise the implementation of the Agreement on Disengagement and maintain the ceasefire with an area of separation known as the UNDOF Zone. Currently there are more than 1,000 UN peacekeepers there trying to sustain a lasting peace. Details of the UNDOF mission, mandate, map and military positions can be accessed via the following United Nations link. Syria and Israel still contest the ownership of the Heights but have not used overt military force since 1974. The great strategic value of the Heights both militarily and as a source of water means that a deal is uncertain. Members of the UN Disengagement force are usually the only individuals who cross the Israeli-Syrian de facto border (cease fire Alpha Line), but since 1988 Israel has allowed Druze pilgrims to cross into Syria to visit the shrine of Abel on Mount Qasioun. Since 1967, Druze brides have been allowed to cross into Syria, although they do so in the knowledge that they may not be able to return.