The Kawah Ijen volcano is a spectacle not only because of its blue fire but also because it hosts the most corrosive lake known to man. With an unbelievable pH of 0.5, the lake has remained a mystery to travelers around the world. So next time you are in Indonesia, plan a visit but don't touch this amazing but corrosive lake!

More information:

geology.com/volcanoes/kawah-ijen