AtIndonesia’s Kawah Ijen volcano, a breathtaking blue glow emerges at night, setting it apart from most volcanoes where lava burns in shades of red. At Kawah Ijen, however, the molten sulfur flows ...

On the slopes of an Indonesian volcano, rivers of light appear to pour out of the dark, glowing an electric blue that looks more like a movie effect than geology. The spectacle is real, but the molten ...