Sol de Manana, a geothermal field in Sur Lipez Province in the Potosi Department, Bolivia, South America

Sulphur tuft fungi (Hypholoma fasciculare) growing on a rotten mossy log in deciduous woodland, Gloucestershire Wildlife Trust Lower Woods nature reserve, Gloucestershire, England, United Kingdom, Europe

Lava flowing into the Pacific Ocean, Volcanoes National Park, Big Island, Hawaii

Ethiopia; Afar region; Danakil Desert; Danakil Depression; Dallol geothermal area; hot sulfur springs; cone-like formation in intense yellow, red and green tones

Pohutu Geyser, Rotorua, Whakarewarewa area, Rotorua, North Island, New Zealand

Puente del Inca, rock arch and old thermal bath of the sulphur spring above the Rio de las Cuevas, near Uspallata, Mendoza Province, Argentina, South America

Hidden bay on the Mediterranean at sunrise. Look at the small beach of sand and pebbles, the beach is bathed in warm colours of the dawn in the morning. View of the sea at Xigia Sulfur Beaches, Zakynthos, Ionian Islands, Greece, Europe

Caldera volcano with pumice fields, yellow coloured sulphur stones, Alexandros crater, Nisyros, Dodecanese, Greece, Europe

Yellow coloured sulphur stones, Alexandros crater, Nisyros, Dodecanese, Greece, Europe

Sulfur vapor, petrified trees in New Blue Spring Road, limestone sinter terraces, steaming geysers, hot springs, Mammoth Hot Springs Terraces in Yellowstone National Park, Wyoming, United States of America

Yellow-coloured sulphur stones, Alexandros crater, Nisyros, Dodecanese, Greece, Europe

R?o Tinto, Andalucia, Spain *** Local Caption *** R?o Tinto ("Red River") is very acidic (Ph 2) and has a deep reddish hue due to iron dissolved in water. The acidity of the watercourse is linked to the drainage of pyrite, which is very present in the subsoil. Extremophilic and endemic bacteria and algae colonize the river bed, forming a fragile biofilm that evokes the hot springs of Yellowstone Park in the USA.

R?o Tinto, Andalucia, Spain *** Local Caption *** R?o Tinto ("Red River") is very acidic (Ph 2) and has a deep reddish hue due to iron dissolved in water. The acidity of the watercourse is linked to the drainage of pyrite, which is very present in the subsoil. Extremophilic and endemic bacteria and algae colonize the river bed, forming a fragile biofilm that evokes the hot springs of Yellowstone Park in the USA.