Gary Bell/ Oceanwide / Coastal rock arch at sunset, Bermagui, New South Wales, Australia

Jeff Foott / Park Avenue view, Arches National Park, Utah

Jeff Foott / Tower Arch, Arches National Park, Utah

Jeff Foott / Marching Men formation, Arches National Park, Utah

Jeff Foott / Marching Men formation, Arches National Park, Utah

Jeff Foott / Double Arch seen through Cove Arch, Arches National Park, Utah

Jeff Foott / Full moon over Balanced Rock formation, Arches National Park, Utah

Jeff Foott / Turret Arch in winter, La Sal Mountains, Arches National Park, Utah

Jeff Foott / Double O Arch, Arches National Park, Utah

Jeff Foott / Turret Arch and the Milky Way, Arches National Park, Utah

Jeff Foott / Mule-ears (Wyethia amplexicaulis) flowers at the The Organ, Arches National Park, Utah

Jeff Foott / Marching Men sandstone formation, Arches National Park, Utah

Jeff Foott / Skyline Arch, Arches National Park, Utah

Jeff Foott / Delicate Arch and the La Sal Mountains, Arches National Park, Utah

Jeff Foott / Winding road and sandstone formations, La Sal Mountains, Arches National Park, Utah

Jeff Foott / Sandstone rock formations, La Sal Mountains, Arches National Park, Utah

Tim Fitzharris / Rock arch, Atuh Beach, Nusa Penida, Bali, Indonesia

Jeff Foott / Fremont Cottonwood (Populus fremontii) trees in autumn, Bentonite Hills, Capitol Reef National Park, Utah

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

Daniel J. Cox / Gray Wolf (Canis lupus) pack on ridge in winter, Lamar Valley, Yellowstone National Park, Wyoming

Chien Lee / Limestone rock formations, Snow Mountains, Papua, Indonesia

Benjamin Olson / Rock formations and mountain range, Cordillera Paine, Torres del Paine National Park, Chile

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) on ridge, Alcedo Volcano, Isabela Island, Galapagos Islands, Ecuador

Tim Fitzharris / Church Rock, volcanic neck formation with view into Monument Valley, Arizona

Tim Fitzharris / The Windows Section from Double Arch at sunrise, Arches National Park, Utah

Tim Fitzharris / The Windows Section from Double Arch at sunrise, Arches National Park, Utah

Tim Fitzharris / Cathedral Rock at sunset, Coconino National Forest, Arizona

Tim Fitzharris / Lightning strike near rock formation, Church Rock, Red Rock State Park, New Mexico

Jeff Foott / Milky way over arch, Turret Arch, Arches National Park, Utah

Yva Momatiuk & John Eastcott / Sandstone rock formations, Vermillion Cliffs National Monument, Arizona

Ingo Arndt / Milky way over sandstone rock formations, Badlands National Park, South Dakota

Ingo Arndt / Sandstone rock formations, Badlands National Park, South Dakota

Ingo Arndt / Sandstone rock formations, Badlands National Park, South Dakota

Ingo Arndt / Sandstone rock formations, Badlands National Park, South Dakota

Ingo Arndt / Sandstone rock formations, Badlands National Park, South Dakota

Colin Monteath/ Hedgehog House / Wildflowers and sandstone rock formation, Flinders Ranges, South Australia, Australia

Colin Monteath/ Hedgehog House / Ayers Rock, Uluru Kata Tjuta National Park, Northern Territory, Australia

Tim Fitzharris / El Arco, Cabo San Lucas, Baja California Mexico

Kevin Schafer / Black-footed Penguin (Spheniscus demersus) group walking near huge stones, Boulders Beach, Cape Peninsula, South Africa

D. Parer & E. Parer-Cook / Volcanic caldera, Daphne Island, Galapagos Islands, Ecuador

Sergey Gorshkov / Tolbachik Volcano erupting, Kamchatka, Russia

Juan Carlos Munoz / Detail of geological rock formations in the sandstone cliffs of Jaizkibel Beach, Gipuzkoa, Basque Country, Spain, May 2012

Juan Carlos Munoz / Man studying the geological rock formations in the sandstone cliffs of Jaizkibel Beach, Gipuzkoa, Basque Country, Spain, May 2012

Linda Pitkin / 2020VISION / Cliffs showing rock striations and geological folding, Pettico Wick, St Abbs (St Abbs and Eyemouth Voluntary Marine Reserve), Berwickshire, Scotland, UK, August 2011

David Welling / Dried grasses and red rock geological formations along the Smithsonian Butte National Scenic byway. Southern Utah, USA, July.

Colin Monteath / Clouds covering Lake Coleridge and Rakaia River from Mount Oakden with Mount Hutt on right, Canterbury, New Zealand

Pete Oxford / Devil's Tower National Monument, Wyoming

Tim Fitzharris / Sandstone striations and erosional features, Badlands National Park, South Dakota

Tim Fitzharris / Full moon over the Grand Canyon at sunset as seen from Pima Point, Grand Canyon National Park, Arizona

Tim Fitzharris / View from Grandview Point looking over sandstone canyons of Monument Basin in the Island in the Sky section of the park, Canyonlands National Park, Utah

Gerry Ellis / Soda and algae formations near shore of Lake Natron, Great Rift Valley, Tanzania

Yva Momatiuk & John Eastcott / Toadstool Caprocks created by erosion, near Paria River, Grand Staircase-Escalante National Monument, Utah

Yva Momatiuk & John Eastcott / Grizzly Bear (Ursus arctos horribilis) pair of spring cubs, Denali National Park and Preserve, Alaska

Tim Fitzharris / Temple of the Sun with Sunflowers in the foreground, Capitol Reef National Park, Utah

Jim Brandenburg / Morning Glory pool in Upper Geyser Basin, Yellowstone National Park, Wyoming

Tui De Roy / Cerro Azul caldera with lake and tufa cone at 5,900 feet, Cerro Azul Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcanic eruption, spatter cone formation and lava fountain from radial fissure, February 1979, Cerro Azul east flank, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcanic eruption, spatter cone formation and lava fountain from radial fissure, February 1979, Cerro Azul east flank, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcanic eruption, spatter cone formation and lava fountain from radial fissure, February 1979, Cerro Azul east flank, Isabella Island, Galapagos Islands, Ecuador

Mike Read / Folded rocks on beach with cliffs above. Sandstone and shale beds in Bude Formation. Bude, Cornwall, England, UK. August 2018

Mike Read / Wave-cut platform on beach. Folded sandstone and shale beds of Bude Formation. Bude, Cornwall, England, UK. August 2018.

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus), Fish Rock, New South Wales, Australia

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus), Fish Rock, New South Wales, Australia

Gary Bell/ Oceanwide / Limestone rock formation, Port Campbell National Park, Victoria, Australia

Gary Bell/ Oceanwide / Coastal rock formation, Dragon Head Rock, Mornington Peninsula, Victoria, Australia

Gary Bell/ Oceanwide / Coastal rock formation, Cape Woolamai, Phillip Island, Victoria, Australia

Gary Bell/ Oceanwide / Rock arch, Tasmans Arch, Tasman National Park, Tasmania, Australia

Gary Bell/ Oceanwide / Limestone rock formation, Port Campbell National Park, Victoria, Australia

Gary Bell/ Oceanwide / Rock arch, London Bridge, Port Campbell National Park, Victoria, Australia

Gary Bell/ Oceanwide / Rock arch, London Bridge, Port Campbell National Park, Victoria, Australia

Gary Bell/ Oceanwide / Rock formation at sunrise, Pulpit Rock, Cape Schanck, Mornington Peninsula, Victoria, Australia

Gary Bell/ Oceanwide / Coastal rock formation, Cape Woolamai, Phillip Island, Victoria, Australia

Gary Bell/ Oceanwide / Coastal rock formation, Cape Woolamai, Phillip Island, Victoria, Australia

Jeff Foott / Rock formation at sunset in winter, Arches National Park, Utah

Jeff Foott / Rock formation, Arches National Park, Utah

Jeff Foott / Trail to Turret Arch, Arches National Park, Utah

Jeff Foott / Balanced Rock formation, La Sal Mountains, Arches National Park, Utah

Jeff Foott / Tower Arch, Arches National Park, Utah

Jeff Foott / Delicate Arch, Arches National Park, Utah

Jeff Foott / The Organ reflected in pool, Arches National Park, Utah

Jeff Foott / The Organ reflected in pool, Arches National Park, Utah

Jeff Foott / Full moon and Balanced Rock, Arches National Park, Utah

Jeff Foott / Icicles and rock formation, Arches National Park, Utah

Jeff Foott / Western Juniper (Juniperus occidentalis) trees and Balanced Rock in winter, Arches National Park, Utah

Jeff Foott / Western Juniper (Juniperus occidentalis) trees and Balanced Rock in winter, Arches National Park, Utah

Jeff Foott / Delicate Arch in winter, Arches National Park, Utah

Jeff Foott / Sandstone formation in mist, Arches National Park, Utah

Jeff Foott / Double Arch seen through Cove Arch, Arches National Park, Utah

Jeff Foott / Sandstone formations, La Sal Mountains, Arches National Park, Utah

Jeff Foott / Delicate Arch, Arches National Park, Utah

Jeff Foott / Skyline Arch, Arches National Park, Utah

Jeff Foott / Sandstone rock formation in winter, Arches National Park, Utah

Jeff Foott / Full moon and Balanced Rock, Arches National Park, Utah

Jeff Foott / Landscape Arch, Arches National Park, Utah

Jeff Foott / Turret Arch in winter, La Sal Mountains, Arches National Park, Utah

Jeff Foott / Sandstone rock formations, La Sal Mountains, Arches National Park, Utah