Geo-thermal power plant, Svartsengi, Iceland

Wairakei Thermal Power Station, Taupo, North Island, New Zealand, Pacific

Pohutu geyser erupting steaming water from sulphurous mud and rock in Te Puia, Whakarewarewa Thermal Reserve in geothermal valley, Rotorua, North Island, New Zealand, Pacific

Diamond Geyser, thermal area, Orakei Korako, South Auckland, North Island, New Zealand, Pacific

Champagne Pools steaming, Waiotapu thermal reserves, Rotorua, North Island, New Zealand

Hot pools and boiling mud at Namaskard thermal area, Hverarond, near Lake Myvatn, North area, Iceland, Polar Regions

Aerial over Trou du Natron with volcano Tousside in the background, Tibesti Mountains, Chad

The endemic Galapagos marine iguana (Amblyrhynchus cristatus) with a lava lizard on top of its head, UNESCO World Heritage Site, Ecuador, South America

The new elevator of the thermal baths using a wastewater-based system, Saint Gervais, Haute-Savoie, France

View of geysers at Geysir Hot Springs in winter, Western Region, Iceland

Geyser in the thermal area at Rotorua, South Auckland, North Island, New Zealand

Leirhnjukur thermal area and eruption site near Krafla geothermal power station, Lake Myvatn, North area, Iceland, Polar Regions

Tourists around the hot mud pools at Namaskard thermal area, Hverarond, near Lake Myvatn, North area, Iceland, Polar Regions

Tourists around the steam jets at Namaskard thermal area, Hverarond, near Lake Myvatn, North area, Iceland, Polar Regions

Steam jet at Namaskard thermal area, Hverarond, near Lake Myvatn, North area, Iceland, Polar Regions

Namaskard thermal area, Hverarond, near Lake Myvatn, North area, Iceland, Polar Regions

Thermal power station, Sabarmati, Ahmedabad, Gujarat, India, Asia

Strokkur geyser erupting, in the Geysir hot springs area, Haukadalur geothermal area, Southwest Iceland

Strokkur geyser erupting, in the Geysir hot springs area, Haukadalur geothermal area, Southwest Iceland

High-tech Gemasolar solar power plant in Fuentes de Andalucia near Seville, solar tower, solar thermal power plant, Andalusia, Spain, Europe