ervation for posterity, which otherwise would be subject to risk from human or animal trespassing, unmonitored, uncontrolled or unrestricted access, or threat from local administrative negligence. Sites are demarcated by UNESCO as protected zones. The World Heritage Sites list is maintained by the international World Heritage Program administered by the UNESCO World Heritage Committee, composed of 21 "states parties" that are elected by the United Nations General Assembly, and advised by reviews of international panels of experts in natural or cultural history, and education. The Program catalogues, names, and conserves sites of outstanding cultural or natural importance to the common culture and heritage of humankind. The programme began with the Convention Concerning the Protection of the World Cultural and Natural Heritage, which was adopted by the General Conference of UNESCO on 16 November 1972. Since then, 196 states have ratified the convention, making it one of the most widely recognised international agreements and the world's most popular cultural program