The longest continuous journey on the Underground is on the Central Line where a journey from West Ruislip to Epping covers just over 34 miles. But the longest journey underground is on the Northern Line: if you travel between Morden and East Finchley, you will travel more than 17 miles underground
The longest distance between stations is on the Metropolitan Line; Chesham is nearly 4 miles from Chalfont & Latimer. The shortest distance is on the Piccadilly Line: Leicester Square and Covent Garden stations being a mere 0.16 miles. With escalators and lifts at each end, it's quicker to walk!
The shortest line on the system is the Waterloo & City which at 1.38 miles easily beats the former holder of the title, the East London Line (five miles) when the former was taken over from British rail in 1994.
A steam train which carried passengers in the 19th Century has returned to mark 150 years since the first tube journey.
A look back at some of the stops on London Underground's 150 year journey.
All day we've been adding fascinating facts about the Tube, which turns 150 years old this week. Now find out how much you know.