The Ijen volcano crater on Indonesia's Java island is one of the world's largest craters. Sulphur mining is a major industry in the region, made possible by an active vent at the edge of a lake, but the work is not without risks. Escaping volcanic gasses are channeled through a network of ceramic pipes, resulting in condensation of molten sulfur. The sulfur, which is deep red in color when molten, pours slowly from the ends of these pipes and pools on the ground, turning bright yellow as it cools. The cooled material is broken into large pieces and carried out in baskets by the miners.