It is believed that this place was Indraprastha the capital city of Pandavas. Many of the present standing monuments were built during the period of Sher Shah Suri. The double-storied octagonal towered mosque is cited in history as the tower from where, Emperor Humayun accidentally fell to his death. The lake at the foothills has boating facilities. One does not have to go far to see the Old Fort or Purana Quila standing stoically amidst wild greenary and disintegrating ramparts. The Purana Quila is roughly rectangular in shape having a circuit of nearly two kilometres. The walls are thick and the three gateways are provided with bastions on either side. The northern gateway called the Talaqui Darwaza or the forbidden gateway combines the typically Islamic pointed arch with Hindu chhattris and brackets. Whereas the southern gateway, called the Humayun Darwaza, had a similar parel with elephants. Humayun who laid the first brick of his new capital Dinapanah in 1534 built the massive gateways and walls of Purana Quila. Sher Shah, who defeated Humayun in 1540, built a few buildings in the complex. Busy traffic runs along this ancient defensive wall built by Sher Shah Suri. The fort, has massive walls and three large gateways. There is a small octagonal red sandstone tower, the Sher Mandal, inside the fort near the South gate. Humayun as a library later used it. While descending the stairs of this tower one day in 1556, he slipped, and received injuries from which he later died. The Qila-i-Kuhran Mosque, or Mosque of Sher Shah, lies just beyond it. There's a small archaeological museum just inside the main gate. There are good views of New Delhi from atop the gate.