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
Line C (Buenos Aires Underground) Line C (Buenos Aires Underground) Line C of the Buenos Aires Underground, that runs from Retiro to Constitución terminus, opened on 9 November 1934, and it has a length of . It runs under such streets as Lima Sur, Bernardo de Irigoyen, Carlos Pellegrini, Esmeralda, la Plaza San Martín and Avenida Ramos Mejia. It not only connects to every other line on the system (with the exception of Line H, which will be connected at a later date), but its termini at Retiro and Constitución also connect it to some of the most important commuter rail networks in Buenos Aires,