Circle line (London Underground) the stations are shared with one or more of the three other sub-surface lines, namely the District, Hammersmith & City and Metropolitan lines. On the Circle and Hammersmith & City lines combined, over 114 million passenger journeys were recorded in 2011/12. The first section became operational in 1863 when the Metropolitan Railway opened the world's first underground line between Paddington and with wooden carriages and steam locomotives. The same year a select committee report recommended an "inner circle" of lines connecting the London railway termini, and the Metropolitan District Railway (commonly known as the District Railway) was formed to build
London Underground persist to this day. "" has a single-player level named "Mind The Gap" where most of the level takes place between the dockyards and Westminster while the player and a team of SAS attempt to take down terrorists attempting to escape using the London Underground via a hijacked train. The game also features the multiplayer map "Underground", in which players are combating in a fictitious Underground station. The London Underground map serves as a playing field for the conceptual game of Mornington Crescent (which is named after a station on the Northern line) and the board game "The London Game".