Jeff Foott / Eureka Dunes, Death Valley National Park, California

Jeff Foott / Eureka Dunegrass (Swallenia alexandrae) on sand dune, Euraka Dunes, Death Valley National Park, California

Jeff Foott / Eureka Dunes and Last Chance Range, Death Valley National Park, California

Jeff Foott / Eureka Dunes and Last Chance Range, Death Valley National Park, California

Jeff Foott / Butte showing sedimentary layers, Death Valley National Park, California

Jeff Foott / Icicles on canyon wall, Zion National Park, Utah

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

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

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

Jeff Foott / Bridge Mountain and Twin Brothers, Zion National Park, Utah

Jeff Foott / Tree and Red Arch Mountain, Zion National Park, Utah

Jeff Foott / Sandstone pedestals, Zion National Park, Utah

Jeff Foott / Bridge Mountain, Zion National Park, Utah

Jeff Foott / Sandstone pedestal, Zion National Park, Utah

Jeff Foott / Bridge Mountain, Zion National Park, Utah

Jeff Foott / Bridge Mountain, Zion National Park, Utah

Jeff Foott / Sandstone formation in winter, Virgin River, Zion National Park, Utah

Jeff Foott / Icicles on canyon wall, Zion National Park, Utah

Jeff Foott / Canyon cliff in winter, Zion National Park, Utah

Jeff Foott / Peaks in winter, Zion National Park, Utah

Jeff Foott / Valley in winter, Zion National Park, Utah

Jeff Foott / Peak in winter, Zion National Park, Utah

Jeff Foott / Peak in winter, Zion National Park, Utah

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

Jeff Foott / Great White Throne, a white sandstone mountain, Zion National Park, Utah

Jeff Foott / Rock formations, Zabriskie Point, Death Valley National Park, California

Jeff Foott / Rock formations, Manly Beacon, Zabriskie Point, Death Valley National Park, California

Jeff Foott / Creek, Salt Creek Trail, Death Valley National Park, California

Jeff Foott / Salt Creek Trail, Death Valley National Park, California

Jeff Foott / Sandstone rock, Zion National Park, Utah

Jeff Foott / Sandstone formation, Zion National Park, Utah

Ingo Arndt / Dwarf Cypress (Taxodium sp) and Pine (Pinus sp) trees in grassland, Everglades National Park, Florida

Jim Brandenburg / Sunset over lake, Lake Vermilion, Minnesota

Jim Brandenburg / Sunset over lake, Pelican Lake, Florida

Kevin Schafer / Cliffs reflected in river, Hittle Bottom, Colorado River, near Castle Valley, Utah

Kevin Schafer / Sunset on Fisher Towers, near Moab, Utah

Kevin Schafer / Sunset on Fisher Towers, near Moab, Utah

Tim Fitzharris / Soaptree Yucca (Yucca elata) and moon, White Sands National Park, New Mexico

Tim Fitzharris / Sand dunes, White Sands National Park, New Mexico

Tim Fitzharris / Sand dune and shrubs, White Sands National Park, New Mexico

Tim Fitzharris / Sand dune and shrubs, White Sands National Park, New Mexico

Tim Fitzharris / Soaptree Yucca (Yucca elata) in sand dune, White Sands National Park, New Mexico

Tim Fitzharris / Florida Mountains, Rockhound State Park, New Mexico

Tim Fitzharris / Mountain, Palo Duro Canyon State Park, Texas

Tim Fitzharris / Wildflowers in canyon, Yankee Boy Basin, San Juan Mountains, Colorado

Tim Fitzharris / Towers of the Virgin, Zion National Park, Utah

Tim Fitzharris / Sand Creek, Great Sand Dunes National Park, Colorado

Tim Fitzharris / Sand dunes and shrubland, Great Sand Dunes National Park, Colorado

Tim Fitzharris / The Organ formation and Virgin River, Zion National Park, Utah

Tim Fitzharris / Towers of the Virgin, Zion National Park, Utah

Tim Fitzharris / Hoodoos, Inspiration Point, Bryce Canyon National Park, Utah

Tim Fitzharris / Sand dunes and river, Great Sand Dunes National Park, Colorado

Tim Fitzharris / Paintbrush (Castilleja sp) flowers, Governor Basin, Colorado

Tim Fitzharris / Reflections in Virgin River after flooding, Zion National Park, Utah

Tim Fitzharris / Rock formations, Virgin River, Court of the Patriarchs, Zion National Park, Utah

Tim Fitzharris / Green River in canyon, Dinosaur National Monument, Colorado

Tim Fitzharris / Ridge and peak, Governor Basin, San Juan Mountains, Colorado

Tim Fitzharris / Butte, Bryce Canyon National Park, Utah

Tim Fitzharris / Turk's Head and Grand Turk peaks, Colorado

Tim Fitzharris / Checkerboard Mesa, Zion National Park, Utah

Tim Fitzharris / Larkspur (Delphinium sp) and Paintbrush (Castilleja sp) flowering, Yankee Boy Basin, San Juan Mountains, Colorado

Sean Crane / Opuntia (Opuntia sp) cactii in desert, Joshua Tree National Park, California

Kevin Schafer / Wind turbines, Schell Creek Range, Nevada

Scott Leslie / Shoreline, Lake Okeechobee, Florida, primary source of the Everglades

Scott Leslie / Path through plain, Everglades National Park, Florida

Scott Leslie / Prairie, Everglades National Park, Florida

Tim Fitzharris / Marsh and trees, Saint George Island, Florida

Michael Durham / Sign forbidding removal of rocks or fossils, Blue Basin, John Day Fossil Beds National Monument, Oregon

Michael Durham / Goose Rock above John Day River, John Day Fossil Beds National Monument, Oregon

Tim Fitzharris / Skyline Drive, Shenandoah National Park, Virginia

Tim Fitzharris / Rock formation called the Lighthouse, Palo Duro Canyon State Park, Texas

Tim Fitzharris / James River, Blue Ridge Parkway, Virginia

Tim Fitzharris / Rockpile, Davis Mountains, Chihuahuan Desert, Texas

Tim Fitzharris / Rockpile, Davis Mountains, Chihuahuan Desert, Texas

Tim Fitzharris / Sandstone mountains, Caprock Canyons State Park, Texas

Norbert Wu / Wave crashing, Carmel, California

Tim Fitzharris / Creek below Pilot Peak and Index Peak, Wyoming

Tim Fitzharris / Phi Kappa Mountain and Summit Creek, Idaho

Tim Fitzharris / Old Faithful geyser spouting, Yellowstone National Park, Wyoming

Tim Fitzharris / Moon over Sawtooth Range, Sawtooth National Recreation Area, Idaho

Tim Fitzharris / Rocks and grassland, Medicine Bow-Routt National Forest, Wyoming

Tim Fitzharris / Pond reflecting Grand Tetons, Grand Teton National Park, Wyoming

Tim Fitzharris / Boulders and Fisher Towers, Professor Valley, Utah

Tim Fitzharris / Pond reflecting Easely Peak, Sawtooth National Recreation Area, Idaho

Tim Fitzharris / Rock outcrops, Curt Gowdy State Park, Wyoming

Tim Fitzharris / Pond reflecting Boulder Mountains, Idaho

Tim Fitzharris / Joshua Tree (Yucca brevifolia) in desert, Spring Mountains, Red Rock Canyon National Conservation Area near Las Vegas, Nevada

Tim Fitzharris / Incoming fog on Mount Rainier, Mount Rainier National Park, Washington

Tim Fitzharris / Mesa near Ghost Ranch, New Mexico

Tim Fitzharris / Bunsen Peak, Yellowstone National Park, Wyoming

Tim Fitzharris / Easely Peak, Sawtooth National Recreation Area, Idaho

Tim Fitzharris / Sandstone formations, Temples of the Sun and Moon, Capitol Reef National Park, Utah

Tim Fitzharris / Coniferous forest succession years after fire, Yellowstone National Park, Wyoming

Tim Fitzharris / Boulder, Split Mountain, Dinosaur National Monument, Utah