Man riding a bicycle downhill, U. S. Route 40, Donner Summit, California, USA

Man mountain biking in a forest viewed through yellow aspen leaves, Lake Tahoe, California, USA

Side profile of a man mountain biking in a forest viewed through yellow aspen leaves, Lake Tahoe, California, USA

Man mountain biking in a forest viewed through yellow aspen leaves, Lake Tahoe, California, USA

Low angle view of a man skiing on powder snow, woman Valley, Fresno County, California, USA

Man riding his mountain bike with a snowboard on his back in winter on Donner Summit, California. USA

Tree stump in sand dunes, Death Valley, Death Valley National Park, California, USA

Sand dunes in a desert, Death Valley National Park, California, USA

Sand dunes in a desert, Death Valley National Park, California, USA

High angle view of rock formations on a landscape, Zabriskie Point, Death Valley, Death Valley National Park, California, USA

Sand dunes in a desert, Mesquite Flat Dunes, Death Valley National Park, California, USA

Sand dunes in a desert, Mesquite Flat Dunes, Funeral Mountains, Death Valley, Death Valley National Park, California, USA

Dead plant in a desert, Mesquite Flat Dunes, Death Valley National Park, California, USA

Sand dunes in a desert, Mesquite Flat Dunes, Death Valley National Park, California, USA

Sand dunes in a desert, Mesquite Flat Dunes, Death Valley National Park, California, USA

Salt lake with a mountain range in the background, Panamint Range, Death Valley National Park, California, USA

Sand dunes in a desert, Mesquite Flat Dunes, Death Valley National Park, California, USA

High angle view of sand dunes in a desert, Death Valley, Death Valley National Park, California, USA

Man cycling on a highway, Death Valley, California, USA