Visit: Yanar Dag, Binagadi-Balakhany Highway, Baku 0125 Azerbaijan
Unlike mud volcanoes, the Yanar Dag flame burns fairly steadily, as it involves a steady seep of gas from the subsurface. There is no seepage of mud or liquid, which distinguishes it from the nearby mud volcanoes
Due to the large concentration of natural gas under the Absheron Peninsula, natural flames burned there throughout antiquity and were reported on by historical writers such as Marco Polo. In the 13th century Marco Polo mentioned numerous natural-gas flames spurting spontaneously from the Absheron Peninsula. The only one burning today is Yanar Dag.
Alexandre Dumas, during one of his visits to the area, described a similar fire he saw in the region inside one of the Zoroastrian fire temples built around it. Only a handful of fire mountains exist today in the world, and most are located in Azerbaijan.