Sachs writes, "The federal preservation movement has roots in the Antiquities Act of 1906, which gave presidents the authority to protect an extraordinary place as a national monument. Congress wields more expansive powers over the landscape. Legislators can name or reassign a site under a wider range of categories." (Size of map dots indicates approximate number of visitors)
But national parks are the most popular, right? Actually, no. "Many travelers might assume that the postcard children of the NPS—Great Smoky Mountains, Yellowstone, Grand Canyon—attract the largest number of annual visitors," Sachs writes. "Golden Gate National Recreation Area in San Francisco and Blue Ridge Parkway flip-flop for the top two spots, with about 15 million visitors each. The Great Smoky Mountains occupies third place with 10 million guests, but it takes first place among the national parks."