Nat Geo Photos : Extreme Earth

Chinstrap penguins (Pygoscelis antarctica) ride out high surf on blue-ice icebergs near Candlemas Island in the South Sandwich Islands. Safe for the moment from predaceous leopard seals, chinstrap penguins are the second most abundant species in Antarctica and the sub-Antarctic.

A storm passes over Yellow Mounds Overlook in South Dakota’s Badlands, casting light and shadow below. Although the region’s name derives from the Oglala Sioux words mako sica or “land bad,” the Badlands showcase the powerful effects of wind and water and contain fossil beds dating to 35 million years ago.

Travertine chimneys near Lake Abbe, Djibouti, were created by hot springs depositing calcium carbonate—the same process that creates stalactites and stalagmites. Some of the formations reach 165 feet (50 meters) near the lake located on the Ethiopia-Djibouti border.

A thick blanket of snow covers West Thumb Geyser Basin in Yellowstone National Park. There are more geysers in this park than anywhere else in the world.

Towers of salt and a riverbed colored by crystallized salt create an otherworldly landscape in Ethiopia’s Danakil Desert. Sitting more than 300 feet (90 meters) below sea level, with temperatures reaching 120 degrees Fahrenheit (49 degrees Celsius), local inhabitants prize the Danakil for one thing: its salt deposits.