...that Arsenal is the only Underground station to be named after a London football club (it was previously known as Gillespie Road)? Watford and West Ham are both named after the areas they serve.
...that the "Mind the gap" announcement is played when trains stop at stations with curved platforms to warn passengers of gaps between the platform edge and the doors?
...that the cause of the Moorgate tube crash in February 1975 was never satisfactorily determined?
...that the original carriages on the City and South London Railway were nicknamed "padded cells" due to their high backed cushioned seats and very small windows?
...that the first version of the Underground roundel was introduced in 1908, as a solid red disk and blue bar?
...that Sir Jacob Epstein's statute Day on the Underground's headquarters at 55 Broadway caused controversy when it was unveiled due to the length of the penis on one of the figures? Epstein later reduced the length.
...that sculptor Henry Moore's first public commission in 1928-29 was a relief sculpture West Wind for the Underground's headquarters at 55 Broadway?
...that a stuffed puffer fish, a samurai sword, human skulls, breast implants and a lawnmower are amongst items handed into TfL's lost property office during its 75-year existence?
...that at 44 tons, the locomotives of the Central London Railway's first underground trains were so heavy that they shook buildings as they passed 60 feet below and were scrapped after three years?
...that the 60 m (197 ft) long escalators at Angel Underground station are the longest on the system?
...that the longest continuous tunnel on the London Underground is 27.8 km (17.25 miles) long, between Morden and East Finchley stations?
...that only 45 per cent of the London Underground is actually underground?
...that at Euston Underground station, a passenger changing between the Victoria line and Northern line Bank branch will find that trains on adjacent platforms travel in opposite directions even though both are either northbound or southbound?
... that the Royal Commission on London Traffic proposed constructing 9 miles (14 km) of avenues with railways underneath at the cost of £30 million in 1905?