Because of the history of the various railways, Paddington is served by four London Underground lines through two separate stations: the Bakerloo, Circle and District lines have a combined sub-surface and deep-level station on Praed Street to the south of the main line station, and the Circle and Hammersmith & City lines have a sub-surface station with access from Paddington Basin to the north. Circle line services run through both of the sub-surface stations as part of a spiral route. Although shown on the London Underground map as a single station, the two stations are not directly linked.