The idea of a national park was first formulated by painter George Catlin. In his travels though the American West, he became concerned about the future of the Native Americans he met and the natural wonders he saw. In 1832 he wrote that they might be preserved,
National parks are usually located in places which have been largely undeveloped, and often feature areas with exceptional native animals, plants and ecosystems (particularly endangered examples of such), or unusual geological features. Occasionally, national parks are declared in developed areas with the goal of returning the area to resemble its original state as closely as possible. In some countries (e.g., United Kingdom) the designation of an area as a national park does not entail national ownership of the land, but simply enforces conservation through planning regulations. UK national parks typically include significant amounts of privately owned land, are used for agriculture, and contain small towns and public roads.
Most national parks have a dual role in offering a refuge for wildlife and as popular tourist areas. Managing the potential for conflict between these two roles can be difficult, particularly as tourists often generate revenue for the parks which can be spent on conservation projects. Occasionally mineral resources are discovered in national parks - if attempts are made to exploit such resources it usually leads to considerable conflict with environmentalists who believe that no such activities should be conducted within these parks.
Some countries (e.g. the U.S.) also designate sites of special cultural, scientific or historical importance as national parks, or as special entities within their national park systems. Other countries use a different scheme for historical site preservation.
In many countries, local government bodies may also maintain park systems. For example, in the US, there are state parks, regional parks, and county parks in addition to the national park system. Generally though not always, the most important sites are national parks.