Trafalgar Square

Trafalgar Square was a large square in the middle of London.

On 23 October 1843, the Fifth Doctor, Tegan Jovanka and Nyssa visited the square. The Doctor climbed Nelson's Column and found its builders Samuel Morton Peto and Thomas Grissell had been taken over by two Sevakrill. In addition, they had installed a missile inside the column which was faced downwards, ready to destroy the Earth in 2017. This would distract the Charnal horde, enemies of the Sevakrill, allowing them to gain a strategic advantage.

To protect this operation, they installed several stone lions, made invisible by perception filters. These lions began chasing Nyssa and Tegan. In the process, they killed seven civilians and a policeman. The Doctor managed to appeal to Peto and Grissell and they broke free.

The lions returned to their plinths and the Doctor hoped that, when their perception filters wore off in a few decades, Sir Edwin Landseer would unveil them as his own creation, as was the case.

The Doctor then spent two weeks lowering the missile into a shaft beneath column and building a floor to cover it. By this time it was November, and the statue of Nelson was being added when the Doctor departed. He left behind a short range sensor in the square to warn him if the Sevakrill ever tried to reactivate the missile. In 1926, the Metropolitan Police Service turned it into a police box. (ST: The Lions of Trafalgar)

Sherlock Holmes and John Watson passed quickly through the square and up Charing Cross Road on their way to Baker Street. (NA: All-Consuming Fire)

The Doctor's TARDIS materialised in Trafalgar Square during the 1965-1966 New Year's Eve celebrations. (DW: The Daleks' Master Plan)

This would have been the same year that Ian Chesterton and Barbara Wright would have visited the Square after returning to Earth (DW: "The Chase")

During the Dalek invasion of Earth in the 2160s, the Daleks patrolled the square. (DW: The Dalek Invasion of Earth)

Nelson's Column was located in the square. (NA: No Future)

Eye of Time Timeline
The Eleventh Doctor and Amy arrived in the Square in 1963 to learn that the Daleks had invaded Earth. The Daleks were chasing the last human through the square. The timeline was restored when the TARDIS crew travelled to Skaro to destroy the Eye of Time. (VG: City of the Daleks)