The step-wells were meant for supply of water and also were used a retreats for the inmates from the heat of summer time. The step-well or the baoli in Agra Fort in Akbari Mahal compound near the Bengali Burj was built by Akbar. For convenience a stairway leads down to the water level. Its purpose was purely utilitarian as is evidenced by the unusual size of the shaft the well being 8m. in diameter and 25m. in depth.
It is six storeyed each with a rotating gallery round the shaft which is 5.4m. in diameter. The lowest storey has no rotating gallery instead it has four flights of steps descending to the water at 24m. below the mouth of the well. The first storey also has whispering galleries and a corridor leading to a site of chambers situated on the north-west in a big storage well. Originally this well must have drawn water from the baoli through the Persian wheel system as is found in the northern water works at Fatehpur Sikri. The second and the third storeys have two spacious octagonal chambers on the east and west sides of the shaft which are the principal features. These rooms evidently served as cool places of retreat during the hot season. The baoli was placed with special relation with the Fort walls in such a position that could draw on the outer air for ventilation through two walls at right angles. The question of ventilation was a very important one in this case, for it must be borne in mind that the well was primarily designed to afford a cool retreat during the heat of the day. This is clearly demonstrated by its intimate connections with the place and its spacious subterranean chambers. The main approach down a wide flight of steps in the thickness of the outer wall is clearly part of the original design of the Fort.