London Underground
The London Underground (also known simply as the Underground, or by its nickname the Tube) is a public rapid transit system serving London and the home counties of Buckinghamshire, Essex and Hertfordshire in the United Kingdom.
The world's first underground railway, the Metropolitan Railway, which opened in 1863, is now part of the Circle, 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. The network has expanded to 11 lines, and in 2014-15 carried 1.305 billion passengers, making it the world's 11th busiest metro system.
