Londen Underground

London is famous for its underground railway system also known as the Tube. The first of these was the Metropolitan Railway, a passenger and goods railway that connected the mainline railway termini at Paddington, Euston and King's Cross to the City. It was opened on 10 January 1863 and served London to 1933. When, in 1871 plans were presented for an underground railway in Paris, it was called the Métropolitain in imitation of the line in London. The modern word metro is a shortened form of the French word.

The world's first underground railway was soon extended from both ends and northwards via a branch from Baker Street. The Metropolitan Railway reached Hammersmith in 1864, Richmond in 1877 and completed the Inner Circle in 1884. The most important route however became the line north into the Middlesex countryside, where it stimulated the development of new suburbs, also known as Metro-land. The Middlesex town of Harrow was reached in 1880, and the line was gradually extended as far as Verney Junction in Buckinghamshire, more than 50 miles (80 kilometres) from Baker Street and the centre of London.

The first tunnels were constructed just below the surface of existing roads using a cut and cover method. Later lines were dug through the London Clay at a deeper (sometimes much deeper) level. The platforms of these deep lines can only be reached via long escalators. Some 55% of the Londen Underground runs above ground, often on embankments or in open cuts.