In this segment of Secrets of Underground London, learn about the history of Aldwych Station, one of the unused stations of the Underground in the heart of London. During the Blitz of WWII, the station was one of the greatest public air raid shelters. It also contains a door to a hidden tunnel, which protected famous artifacts from the British Museum during WWII. The clip also goes underground to explore Churchill's untouched war rooms. Another one of Churchill's underground hiding places, and one of London's greatest WWII secrets, exists in the suburb of Dollis Hill. It is here where Churchill's back-up bunker was housed forty feet below the surface, outfitted with state-of-the-art equipment and built entirely in secrecy.