Twenty National Historic Landmarks (NHLs) are found in the national parks featured in Ken Burns' documentary, The National Parks: America's Best Idea. National Historic Landmark designations are appropriate for park cultural resources that meet National Historic Landmark criteria if the national significance of those resources is not adequately recognized in the park's authorizing legislation or presidential proclamation. Cultural parks may warrant landmark designation as parts of larger areas encompassing resources associated with their primary themes.
The National Park Service is entrusted with the stewardship of the nation's natural resources but our mission also encompasses the protection of our nation's cultural heritage through historic preservation programs like the National Historic Landmarks Program. The NHL Program was established to "preserve historic sites, buildings and objects of national significance for the inspiration and benefit of the people of the United States."