Dawn breaking on the caldera of Mt. Ijen, Banyuwangi Regency, East Java, Indonesia. The kilometer-wide turquoise lake is the largest highly acidic lake on Earth. On its shores is a labor-intensive sulfur mining operation. Miners carry up to 200 lbs from the crater floor up and over the caldera, down into the countryside, where they only get paid around $8-13 USD per load. They make this trip 2-3 times a day.