Jack Dykinga / South rim of Moran Point at sunrise, with the Colorado River below, Grand Canyon National Park, Arizona, USA

Juan Carlos Munoz / Close up of foot of a hiker on the caldera rim of Los Gemelos, Santa Cruz Island, Galapagos, January 2009. Model released.

Fabio Liverani / Tree frog {Hyla sp} on rim of tropical fungus, Tambopata National Reserve, Amazonia, Peru

Jack Dykinga / Ponderosa Pine (Pinus ponderosa) pine cone and needles in the snow, South Rim, Grand Canyon NP, Arizona, USA

Jack Dykinga / Snow on Pinyon Pines (Pinus edulis) at sunrise, East Rim Drive, South Rim, Grand Canyon NP, Arizona, USA

Jack Dykinga / Sunset at Yaki Point on the South Rim with stratified rim rocks and minute storm clouds inside the canyon below, Grand Canyon National Park, Arizona, USA.

Pete Oxford / Sulphur fulmerole in crater of active volcano, Sierra Negra, Isabela Is, Galapagos

Yva Momatiuk & John Eastcott / Coyote (Canis latrans) looking for handouts from tourists, Mather Point parking lot on South Rim, Grand Canyon National Park, Arizona

Tim Fitzharris / South Rim of Grand Canyon with a dusting of snow seen from Yaki Point, Grand Canyon National Park, Arizona

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis vandenburghi) large male on caldera rim, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis vandenburghi) on caldera rim, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis vandenburghi) on caldera rim, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis vandenburghi) group wallowing in seasonal pond on caldera rim, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis vandenburghi) old male in dry season on caldera rim, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis vandenburghi) group wallowing in seasonal pool on caldera rim, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Jack Dykinga / Grandview Point, South Rim, looking east at sunset with receding storm producing double rainbow, Grand Canyon National Park, Arizona, USA. September, 2021.

Paul Williams / Smoke billowing from Mount Bromo volcano. View from the rim of the surrounding caldera known as the sand sea, Bromo Tengger Semeru National Park, Java, Indonesia, July, 2013.

Paul Williams / Smoke billowing from Mount Bromo volcano. View from the rim of the surrounding caldera known as the sand sea, Bromo Tengger Semeru National Park, Java, Indonesia, July, 2013.

Paul Williams / People gathering at the rim of Mount Bromo volcano as morning fog fills the surrounding caldera known as the sand sea, Bromo Tengger Semeru National Park, Java, Indonesia, July, 2013.

Paul Williams / People walking along the narrow rim of Mount Bromo volcano, Bromo Tengger Semeru National Park, Java, Indonesia, July, 2013.

Paul Williams / Village of Cemoro Lawang close to the rim of the caldera known as the sand sea, Bromo Tengger Semeru National Park, Java, Indonesia, July, 2013.

Tui De Roy / Galapagos land iguana (Conolophus subcristatus) tracks around caldera rim Fernandina Volcano, Galapagos .

Tui De Roy / Land Iguana tracks around caldera rim near the summit of Volcan La Cumbre, Fernandina Island, Galapagos .

David Fleetham / View across crater of dormant Haleakala / East Maui Volcano. Haleakala National Park, Maui, Hawaii. March 2016.

Bruno D'Amicis / Wild Apennine wolf (Canis lupus italicus) pup on a forest rim in summer. Central Apennines, Abruzzo, Italy. September. Italian endemic subspecies.

Bruno D'Amicis / Wild Apennine wolf (Canis lupus italicus) pup on a forest rim in summer. Central Apennines, Abruzzo, Italy. September. Italian endemic subspecies.

Jiri Lochman / The rim of the ancient volcanic crater, Border Ranges National Park, Gondwana Rainforest UNESCO Natural World Heritage Site, New South Wales, Australia.

Jiri Lochman / Rim of ancient volcanic crater, Border Ranges National Park, Gondwana Rainforest UNESCO Natural World Heritage Site, New South Wales, Australia.

Inaki Relanzon / Grand Canyon's South Rim, Grand Canyon National Park, Arizona, USA, June 2012.

Chris Mattison / White rim lichen (Lecanora rupicola) growing on a headstone, Gower, South Wales, UK, June.

Kirkendall-Spring / Woman camping on the crater rim of South Sister, Three Sisters Wilderness, Deschutes National Forest. Oregon, USA, July 2014. Model released.

Alex Hyde / The rim of Maliau Basin on the horizon, towering above the dense rainforest it encloses. Maliau Basin, Sabah, Borneo, May 2011.

Michael Pitts / Cameraman and photographer Michael Pitts filming a Giant tortoise on the crater rim of the Alcedo Volcano, Isabela Island. Galapagos.

Michael Durham / Female Allen's lappet-browed bat (Idionycteris phyllotis) in flight at night, near the south rim of the Grand Canyon, Arizona, USA, July.

Michael Durham / Female Allen's lappet-browed bat (Idionycteris phyllotis) in flight at night, near the south rim of the Grand Canyon, Arizona, USA, July.

Michael Durham / Female Allen's lappet-browed bat (Idionycteris phyllotis) in flight at night, near the south rim of the Grand Canyon, Arizona, USA, July.

Jouan Rius / Grand Canyon from Moran Point at sunrise, South Rim, Grand Canyon National Park, Arizona, USA, December 2012.

Jouan Rius / Grand Canyon from Moran Point at sunrise, South Rim, Grand Canyon National Park, Arizona, USA, December 2012.

Jouan Rius / Grand Canyon at sunrise, South Rim, Grand Canyon National Park, Arizona, USA, December 2012.

Jouan Rius / Grand Canyon with Colorado River below, South Rim, Grand Canyon National Park, Arizona, USA, December 2012.

Jouan Rius / Grand Canyon at sunrise, South Rim, Grand Canyon National Park, Arizona, USA, December 2012.

Inaki Relanzon / View from Pima Point on the South Rim of the Grand Canyon, Grand Canyon National Park, Arizona, USA, June

Inaki Relanzon / Rock squirrel (Otospermophilus / Spermophilus variegatus) standing on the South Rim of the Grand Canyon, Grand Canyon National Park, Arizona, USA, June 2012.

Gavin Hellier / View from the rim into the crater of Ranu Kau, Isla de Pascua / Easter Island, Rapa Nui, Chile, 2008

Gavin Hellier / View from the rim into the crater of Ranu Kau, Isla de Pascua / Easter Island, Chile 2008

Gavin Hellier / View from the rim into the crater of Ranu Kau, Isla de Pascua / Easter Island, Chile 2008

Oriol Alamany / Waves along the beach on South Beach Trail, Pacific Rim National Park. Vancouver Island, British Columbia, Canada

Mark Taylor / Rinjani crater rim at sunset, Lombok, Indonesia.