The Purana Qila is situated off Mathura Road, near Delhi Zoo. The Purana Qila occupies the ancient mound which conceals the ruins of the city of Indraprastha of Mahabharata story. Sher Shah Sur, demolished the city of Dinpandh built by Humayun and on the same site raised this citadel. It is irregularly oblong on plan, with bastion on the corners and in the western wall.  Its ramparts cover a perimeter of nearly 2 Km.  It has three main gates on the north, south and west, the last one functioning as the entrance now.  The gates are double-storeyed, built with red sandstone and surrounded by chhatris.

The massive double-storeyed Bara Darwaza (Great Gate) is the main entrance to the fort. The Southern gate is known as Humayun Drawaza. Among the three main gates, the northern one is called the Talaqui - Darwaza (forbidden gate). The exterior of the gate was originally decorated with coloured tiles and the rooms with incised plaster-work.  It is believed that Sher Shah left the Puran-quila unfurnished, and it was completed by Humayun.