Chak Chak Village is located in Ardakan County, 70 km north of Yazd city. The temple of Chak Chak is perched beneath a cliff, which is one of the holy Zoroastrian mountain temples in Iran when the avid Zoroastrians gather on special occasions to observe their rituals. While the temple is a man-made grotto in the cliff, historical beliefs and legends shrouds the sanctuary.
The mystery of the history of Chak Chak Village is a folklore legend as it goes: After the invasion of Arabs to the realm of Sassanid Dynasty and the defeat of the last king, Yazdegerd III, the royal family took refuge in the current city of Yazd. By the time Arabs conquered Yazd, the family separated to increase the chance of survival.
One of Yazdegerd’s daughters, Nikbanu, flees to the Ardakan mountain and Chak Chak Village. And prays to Ahura Mazda (what Zoroastrians call The God) to protect her from Arabs. In response of her sincere supplication, Ahura Mazda commanded the mountain to be opened and safe haven for the chaste lady.
https://irantourismer.com/chak-chak-yazd-pir-e-sabz/