This spot in east Java Island, Indonesia is called Ijen vulcan's crater and is one of only two locations in the world in which blue flames emit from volcanos. The other location is in Iceland. Liquid sulfur becomes alight and produces the "cool," blue fire, which is visible only at night. See a video of the crater below. -Via Science Dump
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The men who work here, without protective gear or machinery, break chunks of sulfur that form when sulfurous steam is cooled into pools of red molten sulfur. They protect themselves from sulfuric acid vapor with damp rags over their faces, and carry baskets with chunks of sulfur on their backs, climbing and walking several miles in and out of the crater.