Exploring America's Newest National Park

America’s National Parks System includes parks, monuments and conservation and historic sites. The federal agency - established in 1916 - is constantly changing. For instance, 26 parks it originally managed have been removed from its list of properties. Some (like Michigan’s Mackinac Island Park) were transferred to state holdings, and others (like South Carolina’s Castle Pinckney Monument) were found to be too expensive to maintain. Erika Celeste reports.