Photographer Olivier Grunewald lost two lenses and a camera in pursuit of these otherworldly images of an Indonesian sulfur mine called Kawah Ijen, but that hardship is nothing compared to the job of the miners, who hike to the top of the peak, descend 660 feet into its crater, then pick up chunks of raw sulfur and slog them back up to the rim in a pair of baskets that hold 100 to 200 pounds.
Sulfur becomes molten at temps just over the boiling point of water and turns into the spectral blue lava you see here. Conditions in the crater aren’t actually hot enough for the sulfur to self-combust — it turns molten when miners drop their torches.
If you’ve ever been around a hot spring, you can only imagine the smell. Grunewald wore a gas mask for his shots (and threw away his clothes afterward), while few of the miners had any such protection. And should you ever find yourself there, careful where you step — that lake is sulfuric acid.