Before dawn, the crater of Kawah Ijen glows blue. Sulfuric gas ignites as it leaves the earth, and electric flames run down the rock like water. It is one of the few places on the planet where this happens. It is also a workplace.

The miners climb into the caldera with cloth pressed against their teeth. They break the hardened sulfur by hand, load it into woven baskets, and carry 70 to 90 kilograms up the crater wall, then three kilometres down the mountain. Most make the trip twice a day.

The long ascent, out of the crater and through the smoke

They call it devil’s gold. The yellow pays for school books and takes years of breath in return.

At the shore of the world’s largest acid lake, the air clears for a moment. The water is a pale, impossible turquoise. Beautiful and lethal at once. The miners rest here between loads and watch tourists photograph the same smoke they will carry an hour later.

This story is about them. The men of Ijen, their humour, their arithmetic of kilograms and rupiah, and what it costs to carry a mountain out of itself.

A brief respite, the acid lake at first light