Malyi Semyachik volcano, acid lake inside summit crater, Kamchatka, East Siberia, Russia

Acid Crater Lake, White Island Volcano, an active volcano in the Bay of Plenty, North Island, New Zealand, Pacific

Kawah Ijen and its turquoise acid crater lake, Java, Indonesia, Southeast Asia, Asia

The very acid Ijen crater lake in the Ijen Volcano, Java, Indonesia, Southeast Asia, Asia

Panorama of sulphur worker appearing out of toxic fumes at Kawah Ijen volcano, East Java, Indonesia, Southeast Asia, Asia

Acid Crater Lake, White Island Volcano, an active volcano in the Bay of Plenty, North Island, New Zealand, Pacific

Acid Crater Lake, White Island Volcano, an active volcano in the Bay of Plenty, North Island, New Zealand, Pacific

Steam plume off boiling acid lake, Naka-dake active crater, Aso volcano, Kyushu, Japan, Asia