The oldest subway in the world, the London Underground serves nearly 274 stations on eleven lines in Greater London. Each line has a color. There are 11 subway lines identifiable thanks to their color. The Bakerloo line is brown, Victoria line sky blue, Central line red, District line green, Northern line black, Circle line yellow, Hammersmith and City line pink, Jubilee line gray, Metropolitan line aubergine, Picadilly line dark blue and finally Waterloo and City line turquoise blue. The orange lines correspond to the network of Overground, the London sky train.
To travel by metro, you must bring either a travelcard or an Oyster card. When you buy your subway ticket, look carefully in which area you want to travel. London is divided into six zones, zones 1 and 2 correspond to central London and zone 6 for example to Heathrow airport. The price of your ticket will depend on the number of zones in which you will travel. Then just go to a subway station and follow the line that corresponds to your destination.
Tube-maps are on sale everywhere in the subway to help you find your route. Alternatively, you can always use the transport for London website where you will find a journey planner, which gives you the route to follow with the duration of your trip and the changes to be made.
It should be noted that applications for Iphone and Android are available, so you can have all the necessary information for your movements on the subway lines in your mobile.
The overground or skytrain
The Overground is described as a suburban rail network or an aerial train. These lines appear in orange on subway maps and you can use your Oyster Card to travel there. The Overground lines serve East, West and North London. Still undergoing repairs, it is quite common for Overground stations to be closed on weekends, so make sure your line is working on TFL.
DLR or Docklands Light Railway
This train line is a subway-owned branch linking the City to Bank, Tower Hill to Beckton, Stratford to the East and North East, and the Docklands, Greenwich and Lewisham to the South. The DLR begins to circulate at 5.30am until midnight Monday to Saturday and from 7am to 11.30pm on Sunday. You can use your Oyster card without problems. For more information, go to TFL)