Brahmajuni Hill, also known as Brahmayoni, is located in the Gaya district, Bihar. The hill top is an important tourist spot which gives a fascinating view of the Gaya town. To reach the top of the hill there are a flight of one thousand stone steps.
The main tourist attraction here at the top is, the two narrow caves called Brahmayoni and Matruyoni caves and temples dedicated to Astabhujadevi and other goddesses. It is said that one can get rid of endless cycles of rebirth by passing through these caves.
The hill is also believed to be the site where Buddha delivered the fire sermon.
Source
http://www.holidayrentals.co.in/articles/details/59/5-Best-Hill-Stations-in-Bihar.html