The places in the National Park System have been set aside for what purposes and for how long?

Since 1872 the United States National Park System has been a natural, historical, recreational, and cultural areas throughout the United States, its territories, and island possessions.

The country's national parks contain volcanoes, glaciers and grass rivers, as well as mountains, valleys and bodies of water. Each park went through a period of discovery, exploration and understanding that must be preserved for future generations. Today the process continues as more land is reserved to be managed by the National Park Service in an effort to preserve the nation's rich natural and cultural history.