The United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Sites are places of importance to cultural or natural heritage as described in the UNESCO World Heritage Convention, established in 1972. Cultural heritage consists of monuments, groups of buildings, and sites. Natural heritage consists of natural features, geological and physiographical formations, and natural sites which are important from the point of view of science, conservation, or natural beauty. UNESCO lists sites under ten criteria; each entry must meet at least one of the criteria. Criteria i through vi are cultural, and vii through x are natural. In addition to sites inscribed on the World Heritage List, member states can maintain a list of tentative sites that they may consider for nomination. Nominations for the World Heritage List are only accepted if the site was previously listed on the tentative list.