This mountain is on fire!
On the edge of a desolate moorland on a small rural road just past the pink salt lake beyond the ugly oil-field turnoff, Yanar Dag (literally Fire Mountain) burns day and night due to the underground gas that was accidentally ignited in 1958.
A decrepit tea house is at the top of a hill, and in the gully is this amazing piece of nature. It's quite nice to sit beside the flames on a cool winter evening.
Is it natural? Well, it once was, but rumor has it that the Azeri government now pipes the gas in. However, there are other places in the area where natural gas seeps out and can be lit, including some springs and water flows. Zoroastrians worshipped fire and built a temple nearby which can still be visited.
Mark Elliot's Azerbaijan