This is an animated timeline showing how the Underground started in 1863, and then grew over the years to present day.
Note that it's showing you when the lines were first created and the Circle Line and Hammersmith & City Line were originally part of the Metropolitan, and District Railways.
The Northern Line extension is currently being constructed from Kennigton - Nine Elms - Battersea, and should be the next new part of the Undergroung on the tube map in 2020.
This animation obviously shows just the London Underground and not the DLR, Overground or future Crossrail services.
The stations in the Hounslow area are really tricky to show (Hounslow Town opened in 1883, closed in 1886, then had a period when it was open again between 1903 and 1909).
The Northern City Line was not originally part of the Northern Line but is shown here in black, as it did later become part of the Northern Line, and appeared on carriage maps of Northern Line trains.
The Waterloo & City line may have opened in 1898, and not 1899!