The Zoroastrians worship fire as the embodiment of the Creator, Ahura Mazda in the material world and the fire in their temples is consecrated out of 16 fires including (as Wikipedia tells me) that of a funeral pyre, a shepherd’s hearth, a goldsmith’s hearth, a potter’s kiln and from a fire caused by lightning.
Loosely translated as ‘Victorious Fire’ or ‘Fire of Victory’ the phrase Atash Behram is derived from the Persian Atash Warharan and is the highest ‘grade’ of a fire that can be placed in a Zoroastrian fire temple.
Udvada’s Atash Behram is the oldest of the nine of its kind, having been established in 1742. Of these, eight are in (western) India and one in Iran.
For some mysterious reason, Zoroastrians in India do not permit people from other faiths to enter their temples, even though the one in Yazd, Iran does.
Inter-religious marriages are also not permitted. A woman marrying outside the community is excommunicated and her children are barred from following the religion. This rule however is tad relaxed for the men. Even though the woman they marry cannot become a Zoroastrian, they get to keep their religion as do their children.
Seen here is a detail from the entrance of the Iranshah Atash Behram in Udvada.