Koryaksky volcano seen beyond walkers on crater rim of Avacha volcano, Kamchatka, East Siberia, Russia

Hikers on rim of old crater, Avacha volcano, Kamchatka, East Siberia, Russia

Group of hikers walking up to Mount Etna summit, UNESCO World Heritage Site, Etna, Sicily, Italy, Mediterranean, Europe

Walkway over lava field, Timanfaya Volcano Interpretation and Visitors' Centre, Lanzarote, Canary Islands, Spain, Atlantic, Europe

Rucu Pichincha Volcano trek, Quito, Pichincha Province, Ecuador, South America, South America

View over the city of Fujiyoshida, Mount Fuji and maples leaves in autumn, Fujiyoshida, Honshu, Japan, Asia

Pichu Pichu volcano (Picchu Picchu) seen from salt flats of Salinas y Aguada Blanca National Reserve, Arequipa Region, Peru, South America

Tourists trekking, Sulphur Lake, Kawah Ijen, Ijen Plateau, island of Java, Indonesia, Southeast Asia, Asia

Trekkers and Oldonyo Lengai volcano, Ngorongoro Conservation Area, Tanzania, East Africa, Africa

Passengers on an expedition cruise climbing the caldera on Deception Island in the South Shetland Islands off the Antarctic Peninsular which is an active volcanic.

Passengers on an expedition cruise climbing the caldera on Deception Island in the South Shetland Islands off the Antarctic Peninsular which is an active volcanic.

Two hikers climb up a rocky volcanic slope, Argentina, Volcanoes, Lava field, Antofagasta, South America

Bromo volcano at sunrise,Tengger Semeru National Park, East Java, Indonesia, Southeast Asia, Asia