Looks beautiful doesn't it? But read my dear old friend Dobs' description below and then thank the lord you're not there:
Kawah Ijen, located in East Java, is a crater lake, the world's largest reserve of sulphuric acid. It is also an important site of sulphur extraction. The vents on the crater floor beside the lake emit toxic fumes and produce bright orange liquid sulphur that yellows during solidification. The deposits are then broken into slabs using crowbars and loaded into baskets for transportation. The steep climb to the crater rim, laden with burdens often in excess of 100 kg, through clouds of thick poisonous gas, is reminiscent of medieval descriptions of hell. Our descent into this inferno was brief and unglorious: we were forced to retreat when a soupy cloud of acidic sulphur gas envelopped us, burning lungs and stinging eyes. Our humiliation was complete when, crawling back up the rocky path, seeking more breathable air close to the ground, we were overtaken by a sulphur miner carrying one and a half times his own bodyweight on his hunched shoulders.
See more of Dobs' pix
here.