London Underground, Train network in London
The London Underground is a public rapid transit system serving London, England.
First opened in 1863, it's the oldest underground metro system worldwide.
Often referred to as 'The Tube', it has become an iconic symbol of the city.
Serves 270 stations and has 11 lines stretching across 250 miles.
Unique for its deep-level tube lines.
Location: Greater London
Location: Buckinghamshire
Location: Hertfordshire
Location: Essex
Inception: 1890
Official opening: January 10, 1863
Website: tfl.gov.uk/modes/tube
Source: Wikimedia