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 (Mac-kan-aw) Island Park) were transferred to state holdings, and others (like South Carolina’s Castle Pinckney Monument) were found to be too expensive to maintain- VOA NEWS