london underground

The London Underground (also known simply as the Underground or as the Tube) is a rapid transit system serving Greater London and some parts of the adjacent home counties of Buckinghamshire, Essex and Hertfordshire in England. It is part of the network of transport services managed by Transport for London.

The Underground has its origins in the Metropolitan Railway, opening on 10 January 1863 as the world's first underground passenger railway. Despite sulphurous fumes, the line was a success from its opening, carrying 9.5 million passengers in the first year of its existence. The Metropolitan is now part of the Circle, District, Hammersmith & City and Metropolitan lines. The first line to operate underground electric traction trains, the City & South London Railway in 1890, is now part of the Northern line.