London Underground

The London Underground was a train network running underneath London.

19th century
The second Doctor seemed to believe the Underground was only built after Victoria Waterfield left Earth in 1866. (DW: The Web of Fear)

There are parts of the Torchwood Hub which were built in a similar style to the old underground stations. (TW: Everything Changes onwards)

20th century
During World War II, a military transit camp was constructed in Goodge Street station. The rooms and corridors remained, shut off from public access, for decades after the war finished. (DW: The Web of Fear)

In 1965, Ian Chesterton and Barbara Wright walked past White City underground station after their return to Earth. (DW: The Chase)

During the Cold War, a hidden elevator was built leading from an Underground station to a top-secret nuclear bunker under Whitehall. (DW: Invasion of the Dinosaurs)

The platforms and tunnels of the Underground were used by the Great Intelligence to pull in the Second Doctor and his companions Jamie McCrimmon and Victoria Waterfield in the TARDIS and have them attacked by its Robot Yetis. (DW: The Web of Fear)

At some point after this adventure, the Brig and the exiled-to-Earth Third Doctor were forced to chase an alien master of disguise throughout the Underground system. The Doctor discovered that the inter-galactic criminal, Hingrad, had dug a secret passage from the bowels of the Tower Hill station to the base of the Tower of London. The Doctor followed Hingrad to the Tower, but was unable to capture him. He did, however, succeed in preventing Hingrad from stealing the Crown Jewels. (PHS: Secret of the Tower)

21st century
Sarah Jane Smith once saved the Underground from a terrorist attack. (BFSJS: Test of Nerve)

In 2005 people outside Queens Arcade station were amongst those attacked by Autons. (DW: Rose)

In 2007 the Tenth Doctor visited Aldgate underground station because it passed close to the chamber where the Water Hive were holding their prisoners. (NSA: The Feast of the Drowned)

In 2009 the Doctor and Majenta Pryce investigated the "ghosts" haunting the Underground and defeated Mnemosyne. (DWM: Ghosts of the Northern Line)

22nd century
A disused underground station was used as a base for resistance fighters against the Dalek occupation. (DW: The Dalek Invasion of Earth)

According to one unreliable source, this station might have been Embankment. (Film: Daleks - Invasion Earth 2150 AD)

The far future
The tunnels and platforms of Marble Arch station survived the fireball when Earth was moved to become Ravolox. A tribe of primitive humans ruled by the robot Drathro resided here. (DW: The Mysterious Planet)

Alternate universes
The First Doctor, Susan, Ian, and Barbara once landed in Canary Wharf station in a universe were WOTAN had never been defeated. (PDA: The Time Travellers)

The Underground also existed in Pete's World. The Tenth Doctor walked past the entrance to St. Paul's station there. (DW: Rise of the Cybermen)

Behind the scenes
On 18th March 2007 BBC4 did a London Underground night in which they broadcast episode 1 of The Web of Fear.