The United Nations Educational, Scientific and Cultural Organization (UNESCO) designates World Heritage Sites of outstanding universal value to cultural or natural heritage which have been nominated by signatories to the 1972 UNESCO World Heritage Convention. 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. The implementation of the World Heritage Convention, the addition or removal of properties from the World Heritage List, and the allocation of funds, among other responsibilities, are managed by the World Heritage Committee. There are twenty-one state members on the committee. Although a term is a maximum of six years, most state parties choose to relinquish their responsibilities after four years so other countries can have the opportunity to be a member of the committee. 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.