The UNESCO, or "United Nations Educational, Scientific and Cultural Organization", created Nov 16 1945, is a specialized agency of the United Nations system. Since 1972, one of the program is to catalog, appoint and retain the so-called cultural or natural importance to the common heritage of mankind. The World Heritage List contains nearly 900 sites around the world.

"Heritage is the legacy of the past, that we enjoy today and that we pass on to future generations."-Abstract from the 1972 Convention -

The main mission of the World Heritage List is to promote and protect sites that the organization considers to be exceptional for cultural, natural or mixed reasons. To be part of the list, a site must meet at least one of the 10 unique criteria applicable to all sites.

1. to represent a masterpiece of human creative genius.
2. To exhibit an important interchange of human values, over a span of time or within a cultural area of the world, on developments in architecture or technology, monumental arts, town-planning or landscape design.
3. To bear a unique or at least exceptional testimony to a cultural tradition or to a civilization which is living or which has disappeared.
4. To be an outstanding example of a type of building, architectural or technological ensemble or landscape which illustrates (a) significant stage(s) in human history.
5. To be an outstanding example of a traditional human settlement, land-use, or sea-use which is representative of a culture (or cultures), or human interaction with the environment especially when it has become vulnerable under the impact of irreversible change.
6. To be directly or tangibly associated with events or living traditions, with ideas, or with beliefs, with artistic and literary works of outstanding universal significance. (The Committee considers that this criterion should preferably be used in conjunction with other criteria.).
7. To contain superlative natural phenomena or areas of exceptional natural beauty and aesthetic importance.
8. 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.
9. 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.
10. To contain the most important and significant natural habitats for in-site conservation of biological diversity, including those containing threatened species of outstanding universal value from the point of view of science or conservation.