When you’re in the mine, the sky is covered by gases. Day and night are confused. You feel suspended in time. Sunarto, 41 years old, carries a load of sulfur out of the Kawah Ijen crater.

Volcanic activity at the Kilauea volcano in Hawaii is producing blue fire. The flames are caused by methane gas, a byproduct of the lava being spewed out by the volcano. Authorities warned that ...