Many tube stations were used as air-raid shelters during the Second World War, but the Central Line was even converted into a fighter aircraft factory that stretched for over two miles, with its own railway system. Its existence remained an official secret until the 1980s.
The longest distance between stations is on the Metropolitan line from Chesham to Chalfont & Latimer: a total of only 3.89 miles.
The longest continuous tunnel is on the Northern line and runs from East Finchley to Morden (via Bank), a total of 17.3 miles.
The total length of the London Underground network is 249 miles.
Over 47 million litres water are pumped from the Tube each day, enough to fill a standard leisure centre swimming pool (25 metres x 10 metres) every quarter of an hour.
The District Line has the most stations: 60.
Tube trains travelled 72.4 million train kilometres (45 million miles) last year.
One of the early names proposed for the Victoria Line was the Viking line.
The first escalator on the Underground was installed at Earl’s Court in 1911.
Sting and Paul McCartney are both rumoured to have busked on the Underground in disguise.
Approximately 50 passengers a year kill themselves on the Underground.
A sobering statistic is that the most popular tube suicide time is around 11 am.
The last manually operated doors on Tube trains (replaced by air-operated doors) were phased out in 1929.