Tim Fitzharris / Mae Ya Waterfall cascading 260 meters, Doi Inthanon National Park, Thailand

Paul Bertner / River in tropical rainforest at dusk, Tambopata Research Center, Peru

Jeff Foott / Rock formation, Metate Arch, Devil's Garden, Grand Staircase-Escalante National Monument, Utah

Jeff Foott / Round boulders, Theodore Roosevelt National Park, North Dakota

Jeff Foott / Sandstone rock formations, Theodore Roosevelt National Park, North Dakota

Jeff Foott / Sandstone rock formations, Theodore Roosevelt National Park, North Dakota

Jeff Foott / Sandstone rock formations, Theodore Roosevelt National Park, North Dakota

Shane P. White / Opuntia (Opuntia echios) cacti, Santa Cruz Island, Galapagos Islands, Ecuador

Heike Odermatt / River flowing through canyon, Fjadrargljufur Canyon, Iceland

Jeff Foott / Broken Bow Arch, Grand Staircase-Escalante National Monument, Utah

Jeff Foott / Seastack at Harris Beach State Park, Oregon

Jeff Foott / Racetrack Playa with mysterious 'sailing stones', Death Valley National Park, California

Jeff Foott / Racetrack Playa with mysterious 'sailing stone', Death Valley National Park, California

Jeff Foott / Sand dune, Mesquite Flat Sand Dunes, Death Valley National Park, California

Hiroya Minakuchi / Glacier, Spitsbergen, Svalbard, Norway

Tim Fitzharris / Mae Ya Waterfall cascading 260 meters, Doi Inthanon National Park, Thailand

Tim Fitzharris / Rock formation and palm trees on beach, Hidden Beach, Palawan, Philippines

Jeff Foott / Fremont Cottonwood (Populus fremontii) trees and rock formation, The Castle, Capitol Reef National Park, Utah

Jeff Foott / Round boulders, Theodore Roosevelt National Park, North Dakota

Jeff Foott / Round boulders, Theodore Roosevelt National Park, North Dakota

Jeff Foott / Fremont Cottonwood (Populus fremontii) trees and rock formation, The Castle, Capitol Reef National Park, Utah

Jeff Foott / Round boulders, Theodore Roosevelt National Park, North Dakota

Tim Fitzharris / Pine (Pinus sp) trees at sunrise, St. Joseph Bay State Buffer Preserve, Florida

Chase Dekker / River in canyon, Fjadrargljufur Canyon, Iceland

Ingo Arndt / Mountains reflected in lake, Paine Massif, Torres del Paine, Torres del Paine National Park, Patagonia, Chile

Ingo Arndt / Paine Massif, Torres del Paine, Torres del Paine National Park, Patagonia, Chile

Ingo Arndt / Mountains reflected in lake, Paine Massif, Torres del Paine, Torres del Paine National Park, Patagonia, Chile

Shane P. White / Christ the Redeemer statue, Rio de Janeiro, Brazil

Hiroya Minakuchi / Sand dune at sunrise, Namib Desert, Namibia

Hiroya Minakuchi / Cumulonimbus clouds over rainforest, Kinabatangan River, Malaysia

Tim Fitzharris / Colorful rock formations, Rainbow Vista, Valley of Fire State Park, Nevada

Shane P. White / Pagoda at dusk, China

Shane P. White / Pagoda, Grand Palace Complex, Phnom Penh, Cambodia

Tim Fitzharris / Butte in desert, Valley of the Gods, Utah

Tim Fitzharris / Butte in desert, Valley of the Gods, Utah

Shane P. White / Coastline, Snaefellsnes, Iceland

Tui De Roy / Opuntia (Opuntia echios) cacti surrounded by Sea-purslane (Sesuvium edmonstonei), Plazas Island, Galapagos Islands, Ecuador

Tui De Roy / Opuntia (Opuntia echios) cacti, Santa Fe Island, Galapagos Islands, Ecuador

Tui De Roy / Opuntia (Opuntia echios) cactus, Santa Fe Island, Galapagos Islands, Ecuador

Tui De Roy / Sea-purslane (Sesuvium edmonstonei), Punta Pitt, San Cristobal Island, Galapagos Islands, Ecuador

Tim Fitzharris / Twin Lakes, Mammoth Lakes, Inyo National Forest, Sierra Nevada, California

Tim Fitzharris / Mountains at sunrise, Mount Whitney, Sierra Nevada, California

Tim Fitzharris / San Juan Mountains from Little Molas Lake, Colorado

Tim Fitzharris / Mountain, Mount Sneffels Wilderness, Colorado

Tim Fitzharris / East River and Cinnamon Mountain, Raggeds Wilderness, Colorado

Jeff Foott / Cumulus clouds over sandstone, Lake Powell, Glen Canyon National Recreation Area, Utah

Jeff Foott / Gregory Butte, Lake Powell, Glen Canyon National Recreation Area, Utah

Jeff Foott / Butte, Last Chance Canyon, Lake Powell, Glen Canyon National Recreation Area, Utah

Jeff Foott / Sandstone rock formations, Last Chance Canyon, Lake Powell, Glen Canyon National Recreation Area, Utah

Jeff Foott / Sandstone rock formations, Last Chance Canyon, Lake Powell, Glen Canyon National Recreation Area, Utah

Jeff Foott / Dominguez Butte, Lake Powell, Glen Canyon National Recreation Area, Utah

Jeff Foott / Cumulus clouds over sandstone, Lake Powell, Glen Canyon National Recreation Area, Utah

Tim Fitzharris / Peak, Red Mountain Pass, Colorado

Tim Fitzharris / Moon and desert, Little Missouri River, Theodore Roosevelt National Park, North Dakota, digital composite

Tim Fitzharris / Lackawanna Lake, Lackawanna State Park, Pennsylvania

Tim Fitzharris / Tuwa Creek, Natural Bridges National Monument, Utah

Tim Fitzharris / Rock arch, Hickman Bridge, Capitol Reef National Park, Utah

Tim Fitzharris / Sand dune, Coral Pink Sand Dunes State Park, Utah

Jeff Foott / Junction Butte and sandstone formations in Monument Basin at sunrise, Canyonlands National Park, Utah