World Heritage sites are selected on the basis of six cultural and four natural criteria. To be included on the World Heritage List, sites must be of outstanding universal value and meet at least one of the selection criteria--
Natural Criteria
(vii) to contain superlative natural phenomena or areas of exceptional natural beauty and aesthetic importance;
(viii) to be outstanding examples representing major stages of earth's history, including the record of life, significant on-going geological processes in the development of landforms, or significant geomorphic or physiographic features;
(ix) to be outstanding examples representing significant on-going ecological and biological processes in the evolution and development of terrestrial, fresh water, coastal and marine ecosystems and communities of plants and animals;
(x) to contain the most important and significant natural habitats for in-situ conservation of biological diversity, including those containing threatened species of outstanding universal value from the point of view of science or conservation.