Paul D Stewart / Aerial view of Grand Prismatic thermal spring in Yellowstone National Park, USA. The bright colours are natural, coming from thermophile bacteria in the water. People can be seen walking on the raised...

Jeff Vanuga / Thermal hot spring at Mud Volcano, Hayden Valley, Yellowstone National Park, Wyoming, USA.

Jeff Vanuga / Dead Thermal Spider encased in thermophilic bacteria in hot Spring, Yellowstone National Park, Wyoming, USA, October

Ingo Arndt / Japanese macaques grooming in hot thermal spring {Macaca fuscata} Joshin-etsu NP, Japan. These primates can survive winter temperatures below -15 degrees by bathing in the springs

Colin Monteath / Champagne Pool as burst of sunshine lights up foreshore during day with blowing mist and heavy rain, Waiotapu Thermal Wonderland, Rotorua, New Zealand

Colin Monteath / Champagne Pool as burst of sunshine lights up foreshore during day with blowing mist and heavy rain, Waiotapu Thermal Wonderland, Rotorua, New Zealand

Colin Monteath / Rain storm approaches Champagne Pool, volcanic lake has constant 74 degree Celsius water including minerals gold, silver mercury, sulphur, and arsenic, Wai-O-Tapu Thermal Wonderland, Rotorua, North Is...

Colin Monteath / Rain storm approaches Champagne Pool, volcanic lake has constant 74 degree Celsius water including minerals gold, silver mercury, sulphur, and arsenic, Wai-O-Tapu Thermal Wonderland, Rotorua, North Is...

Jeff Vanuga / Thermal runoff from Grand Prismatic Spring into the Firehole River, Yellowstone National Park, Wyoming, USA, October 2008

Igor Shpilenok / Thermal waters rise from a spring rimmed with a colony of thionic bacteria in the caldera of the Uzon Volcano in July, Kronotsky Zapovednik, Kamchatka, Far East Russia

Shaun Barnett / Ohaaki Pool, thermal district near Taupo, New Zealand

Gavin Maxwell / Hot Spring Snake (Thermophis baileyi) on shoreline of thermal spring. Yangpachen, Tibet

Gavin Maxwell / Hot Spring Snake (Thermophis baileyi) in thermal spring. Yangpachen, Tibet

Konrad Wothe / Champagne pool, Waiotapu Thermal Wonderland, North Island, New Zealand

Konrad Wothe / Champagne pool, Waiotapu Thermal Wonderland, North Island, New Zealand

Michael & Patricia Fogden / Lady Knox Geyser in Waiotapu thermal basin, Rotorua, North Island, New Zealand

Tui De Roy / Geothermal activity, steaming mineral hot springs shaped like the Americas, Geyser Thermal Field, Iceland

Tui De Roy / Geothermal activity, steaming mineral hot springs, Geyser Thermal Field, Iceland

Tui De Roy / Champagne Pool, a volcanic lake has constant 74 degree Celsius water including minerals gold, silver mercury, sulphur, and arsenic, Waiotapu, Rotorua, New Zealand

Doug Perrine / Florida manatees gather near warm spring in winter {Trichchus manatus latirostris} Blue Springs SP, Florida, USA (Non-ex).

Colin Monteath / Champagne Pool as burst of sunshine lights up foreshore during day with blowing mist and heavy rain, Waiotapu Thermal Wonderland, Rotorua, New Zealand

Colin Monteath / Rain storm approaches Champagne Pool, volcanic lake has constant 74 degree Celsius water including minerals gold, silver mercury, sulphur, and arsenic, Wai-O-Tapu Thermal Wonderland, Rotorua, North Is...

Konrad Wothe / Wai-o-tapu Thermal Wonderland near Rotorua, Devils Bath, North Island, New Zealand

Tui De Roy / Geothermal activity, mineral hot pools, geyser thermal field, Iceland

David Pike / Japanese macaques in hot springs {Macaca fuscata} Jigokudani Japan