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 countries which are signatories to 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. Yemen ratified the convention on 7 October 1980.