From The Big Picture:
In East Java, Indonesia lies Kawah Ijen volcano, 2,600 meters tall (8,660ft), topped with a large caldera and a 200-meter-deep lake of sulfuric acid. The quietly active volcano emits gases through fumaroles inside the crater, and local miners have tapped those gases to earn a living. Stone and ceramic pipes cap the fumaroles, and inside, the sulfur condenses into a molten red liquid, dripping back down and solidifying into pure sulfur. Miners hack chunks off with steel bars, braving extremely dangerous gases and liquids with minimal protection, then load up as much as they can carry for the several kilometers to the weighing station. Loads can weigh from 45 to 90kg (100 – 200 lbs), and a single miner might make as many as two or three trips in a day. At the end of a long day, miners take home approximately Rp50,000 ($5.00 u.s.). The sulfur is then used for vulcanizing rubber, bleaching sugar and other industrial processes nearby.