The 'Lal Qila' or Red Fort was built by the Mughal Emperor Shah Jahan (r.1628-1658) at his new capital Shahjahanabad at Delhi on the banks of the river Jumna. It derives its name from the red sandstone which is the dominant building material. It was the seat of Mughal power until the Uprising of 1857 when Bahadur Shah the last Mughal Emperor was dethroned. The principal gates of the Red Fort, or Lal Qila are the Lahore, Delhi and Water Gate. It is surrounded by a deep moat, however this has been dry since 1857. Originally wooden drawbridges spanned this moat, but these were replaced by stone bridges in 1811. The walls of the fort are constructed from red sandstone with a series of bastions, kiosks and turrets. The original layout included residential palaces, a mosque, halls of public and private audience, a harem and formal gardens and pavilions.