Jeff Foott / Morning Glory Pool, Upper Geyser Basin, Yellowstone National Park, Wyoming

Jeff Foott / Fumaroles, Porcelain Basin, Norris Geyser Basin, Yellowstone National Park, Wyoming

Jeff Foott / Geyser spouting, Old Faithful, Yellowstone National Park, Wyoming

Shane P. White / Japanese Macaque (Macaca fuscata) in hot spring, Jigokudani, Nagano, Japan

Yva Momatiuk & John Eastcott / Rhyolite mountains and geothermal vents, Kerlingarfjoll, Iceland

Jami Tarris / Japanese Macaque (Macaca fuscata) in hot spring, Jigokudani, Nagano, Japan

Hiroya Minakuchi / Japanese Macaque (Macaca fuscata) young in hot spring, Jigokudani, Japan

Thomas Marent / Japanese Macaque (Macaca fuscata) mother and young in hot spring with juveniles grooming, Jigokudani, Nagano, Japan

Fiona Rogers / Japanese Macaque (Macaca fuscata) pair grooming in a geothermal spring, Jigokudani Monkey Park, Japan

Fiona Rogers / Japanese Macaque (Macaca fuscata) baby in a geothermal spring, Jigokudani Monkey Park, Japan

Fiona Rogers / Japanese Macaque (Macaca fuscata) baby sucking its toe in a geothermal spring, Jigokudani Monkey Park, Japan

Alex Mustard,Alex Mustard / A diver and a hydrothermal chimney. Note that he is obscured by the different temperature waters (from the chimney and the surrounding water) which are unable to mix. The sea water was 4 degrees Celsi...