The article gives no confirmed builder or date. Scholars often propose the 17th century, and inscriptions span Samvat 1725 to 1873, about 1668 to 1816, with two dated 1745. A foundation stone cited by Modi gives about 1810. A press report attributes the complex to Hindu and Sikh traders in Baku, and the article names no architect.
The complex is pentagonal, with a central courtyard surrounded by cells that housed ascetics and pilgrims. A tetrapillar altar stands in the middle, and a trident tops the structure. George Forster described it in 1784 as a square of about 90 feet (27 m) with many apartments, each with a small sulphurous fire jet.
The style is disputed. The infobox lists Achaemenid, J. Unvala called it pure Sasanian, and the article says the present shrine has a Northern Indian foundation. Natural gas fed the flame until 1969, and mains gas feeds it now. It became a museum in 1975.

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