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

Arne Hodalic / Nenet herdsman with Reindeer (Rangifer tarandus) during summer migration, Yamal Peninsula, Russia. May.

Sven Zacek / Cross-country skiier on a moonlit night admiring the Northern Lights (Aurora borealis), Norway, March 2013.

Shibai Xiao / State-owned forestry plant with workers lifting logs early in the morning, Heilongjiang Provinc, China, January 2010. No release available

Chadden Hunter / Cameraman Jeff Turner and Producer Chadden Hunter exposed at -40 degrees in Arctic circle in Northern Canada while filming wolves and bison hunting sequence. Taken on location for BBC Frozen Planet se...

Bryan and Cherry Alexander / Khanty herder standing on sled, with Reindeer / Caribou (Rangifer tarandus). Khanty Mansiysk, Western Siberia, Russia, 2000.

Bryan and Cherry Alexander / Chukchi men resting their Huskies (Canis familiaris) during hunting trip. Chukotskiy Peninsula, Chukotka, Siberia, Russia.

Bryan and Cherry Alexander / Chukchi hunters travelling with Huskies (Canis familiaris) near Cape Dezhnev. Chukotskiy Peninsula, Chukotka, Siberia, Russia.

Steven Kazlowski / Photographers photographing of a group of curious Polar bears (Ursus maritimus) from motorboats along a barrier island during autumn freeze up, Barter Island, 1002 area of the Arctic National Wildlife...

Bryan and Cherry Alexander / Tourist photographing group of Sami men in traditional costume. Kautokeino, Norway, 1972.

Jeff Wilson / Film crew lowering camera into crevasse in Gorner glacier, near Zermatt in the Swiss Alps, Switzerland, for BBC Planet Earth series, Mountains episode, 2006

Jeff Wilson / Rear view of pilots and Trango towers in the Karakoram Mountains, Himalayas, Pakistan, from Pakistani military helicopter, for BBC series Planet Earth. April 2005