Ubehebe Crater in Death Valley National Park, California, USA

Ubehebe Crater is a volcanic crater in the northern half of California’s Death Valley National Park. The crater, which is 800 metres wide and up to 237 metres deep, is the largest of about a dozen craters in the Ubehebe volcanic field. In geological terms, Ubehebe and the other craters here are quite young. A 2016 study concluded that the craters were all formed in a relatively brief series of explosions – a period of days or weeks – about 2,100 years ago. Another eruption could happen, but visitors don’t need to worry about the ground below their feet – seismometers in the area will alert geologists in advance of any future volcanic unrest. A trail around the rim of the crater offers views of the colourful layers of stone along the walls. Hikers can descend to the bottom, but it's a long trek back out again, especially on a sweltering summer day.
© Albert Knapp/Alamy