London Tube

The London Underground is a metro system serving a large part of Greater London and neighbouring areas of Essex, Hertfordshire and Buckinghamshire in the UK. The first section opened in 1863, making it the first underground railway system in the world,^[4] and, starting in 1890, it was the first to operate electric trains.^[5] It is usually referred to as the Underground or the Tube—the latter deriving from the shape of the system's deep-bore tunnels—although about 55% of the network is above ground.