The Kawah Ijen Volcano in Indonesia (see body text for reasoning)
unreal deep blue/purple flames can be seen emerging from the Kawah Ijen Volcano in Java, Indonesia. the cause of the flames being this color is due to large amounts of sulfuric acid that emerge with the lava, with so much being present that it gives the lava this vibrant color CREDIT: buzzfeed.com (article) republicworld.com (photo)