A national park is a park in use for conservation purposes. Often it is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently, there is a common idea: the conservation of wild nature for posterity and as a symbol of national pride.
Furthermore, an international organization, the International Union for Conservation of Nature (IUCN), and its World Commission on Protected Areas, has defined "National Park" as its Category II type of protected areas.
While ideas for this type of national park had been suggested previously, the United States established the first such one, Yellowstone National Park, in 1872. The largest national park in the world meeting the IUCN definition is the Northeast Greenland National Park, which was established in 1974. According to the IUCN, there were 6,555 national parks worldwide in 2006 that meet its criteria. IUCN is still discussing the parameters of defining a national park.
National parks are almost always open to visitors. Most national parks provide outdoor recreation and camping opportunities as well as classes designed to educate the public on the importance of conservation and the natural wonders of the land in which the national park is located.