The World Heritage Committee, has included 38 treasures from Spain in the list of Heritage of Mankind. In order to be included in this list, they must comply with certain criteria of selection. These criteria are gathered in the Working Guide Lines ; the main document of the Committee. The criteria, which are periodically revised by the Committee, have evolved in parallel with the development of the concept of World Heritage. So between 1978 and 1997 the criteria Natural and Cultural evolved considerably. Therefore, depending on the date of inclusion in the list, the criteria for it have been different in each case. Nevertheless, in every case the objective is to ensure that future generations can inherit the treasures of the past. We now enumerate the criteria of the Committee to include the treasures mentioned above in the list of World Heritage:
I Represent a masterpiece of the human creative genius, or
II To be the manifestation of a considerable exchange of human values for a determined period or in a specific cultural area, in the development of architecture, monumental arts, urban planning or landscape design, or
III Contribute with a unique testimony, or at least exceptional, of a cultural tradition or of a civilization, still existing or extinct, or
IV To be an outstanding example of a building or an architectural or technological complex, or a landscape that illustrates a significant period or periods of the history of mankind, or
V Constitute an outstanding example of habitat or traditional human settlement or of the usage of the land that represents a culture or cultures, specially if they have become vulnerable through irreversible changes, or
VI To be associated directly or perceptibly with events or live traditions, with ideas or beliefs or with artistic or literary works of an exceptional and universal significance (the Committee considers that this criteria only justifies the inscription in the list on exceptional circumstances and on a joint application with other cultural or natural criteria).
I To be exceptional examples that represent the different periods in the history of the Earth, including the record of the evolution, of the current significant geological processes, the development of the earthly structures or of geomorphological or physiographical elements of significance, or
II To be examples, eminently representative, of current ecological (environmental) and biological processes, in the evolution of the ecosystems and the colonies of plants and animals, terrestrial, aquatic, coastal and marine, or
III To comprise extraordinary natural phenomena or areas of a natural beauty and exceptional aesthetic importance, or
IV To contain the most important natural habitats and the most representative for the conservation on site of the biological diversity, including those that hold threatened species of outstanding universal value, from the point of view of science, conservation or natural beauty.