Flagstaff Tower is a one-room, castellated tower, built around 1828 as a signal tower, located in Kamla Nehru Ridge near the present-day North Campus of Delhi University in Delhi, India. It was here that many Europeans and their families sheltered on 11 May 1857, during the Siege of Delhi by the rebels at the beginning of the Indian rebellion of that year, waiting for help to arrive from nearby Meerut.