What is the London Underground?
The London Underground, known as the Tube, is London's metro system and the oldest underground railway in the world. It opened in 1863 and now has 11 lines serving 272 stations.
The first section, the Metropolitan Railway, opened on 10 January 1863 between Paddington and Farringdon. Early trains were pulled by steam locomotives.
The deep-level tube lines, built in round tunnels, gave the system its nickname, the Tube. The City and South London Railway, opened in 1890, was the first deep-level electric railway.
Lines and landmarks
The 11 lines include the Central, Northern, Piccadilly, Victoria and Jubilee lines. Each has its own color on the Tube map. The Elizabeth line and the Overground are separate rail services shown on the same map.
The Underground carries millions of passengers on busy days. Its red, white and blue roundel logo is one of the world's most recognizable symbols.
During World War II, many stations were used as air raid shelters during the Blitz. The famous announcement mind the gap warns passengers about the space between the train and the platform. Night Tube services run on some lines on Friday and Saturday nights.