Photographer Olivier Grunewald has recently made several trips into the sulfur mine in the crater of the Kawah Ijen volcano in East Java, Indonesia, bringing with him equipment to capture surreal images lit by moonlight, torches, and the blue flames of burning molten sulfur. Covered last year in the Big Picture (in daylight), the miners of the 2,600 meter tall (8,660ft) Kawah Ijen volcano trek up