The gems in America's jewel box: US National Park Service turns 100

Exactly 100 years since the US National Park Service began, the agency is still devoted to operating and preserving numerous sites including Yellowstone, the Grand Canyon, and the National Mall in Washington.

To mark the occasion, the Smithsonian's Natural History Museum has opened a photo exhibit dedicated to the parks. The BBC's Jane O'Brien went for a look.

Filmed by Maxine Collins, edited by Bill McKenna, produced by Mat Morrison