The Ateshgah, the Fire Temple, is a pentagonal stone caravanserai-fortress about thirty kilometres east of Baku, built in the seventeenth and eighteenth centuries by Hindu, Sikh, and Zoroastrian fire-worshippers around a natural gas vent that burned continuously at its centre. The flame in the central altar today is fed by piped gas — the original vents stopped burning in the 1960s when surrounding industrial drilling reduced the pressure — but the building is otherwise intact.
The cells around the courtyard once housed pilgrims and ascetics. Several have been turned into displays explaining the religious mix that once converged here: Persian Zoroastrians, Indian merchants from the Multani caravan trade, and Sikhs from Punjab all left inscriptions. It is one of the more unexpected religious sites in the Caucasus and well worth the half-day trip.