Ateshgah, also known as the Temple of Eternal fire is a unique place - both naturally and historically. In ancient times this was a Holy Place for the Zoroastrians who used to worship fire, and that's why this eternal and indistinguishable fire was remarkably valuable and symbolic for them. But how exactly is that possible? The "eternal fire" is a natural phenomenon, which is actually the burning of natural gas from the earth crust. When the fire comes out on the surface of the earth and meets the oxygen, it lits up. The Temple of Eternal fire consists of a lot of such burning little holes. Anyway, the natural fire stopped burning sometime during the 19th century due to some movement in the Earth surface. Nowadays the Temple is lit by artificial fires which resemble what it once was.