Yanardag, located approximately 27 km from Baku, literally means the "burning mountain". The type of mud volcano - the source of Yanardag’s fire that has presumably been burning for more than 20,000 years - is ignited when the natural gas leaking from the rocks comes into contact with air. The natural fires that result have fascinated travellers (including Marco Polo) throughout the ages.  Many traditions and faiths, including Shamanism and Zoroastrianism, have been shaped around fire. As the former structure at Yanardag was primitive, the Azerbaijan tourism agency upgraded to a full-fledged Museum and Visitor Centre, with indoor and outdoor exhibition areas, a café, workshop, amphitheatre, and walkways. Although unfinished due to budgetary constraints, the site is connected to the other side of the small valley with a pedestrian bridge that provides a view of fire in the lower levels of the terrain.  

Source: Aga Khan Trust for Culture