In this amazing close-up by Olivier Grunewald, we see molten sulfur burning atop a solid sulfur deposit. The picture was taken at the sulfur mine located in the crater of the Kawah Ijen volcano in East Java, Indonesia.
Ijen is a 20 kilometers wide caldera, which houses more volcanoes in it. One of them is the Kawah Ijen volcano, which is filled with sulfur. When it burns the blue flames appear – the site is especially amazing at night.