Buckingham Palace

Buckingham Palace was a palace in London where the British monarchy resided.

21st century
In 2008, during the reign of Elizabeth II, most residents of London left the city out of fear over an alien invasion. Elizabeth II herself chose to stay behind. A starship fashioned after the Titanic was about to crash into the palace until the Doctor, at the controls, managed to avert the disaster. (DW: Voyage of the Damned (TV Story))

The Doctor had also parked his TARDIS in the grounds of Buckingham Palace prior to the events of (DW:Planet of the Dead)

Alternative timelines

 * In one timeline, the Titanic did crash into the Palace, causing a nuclear explosion. (DW: Turn Left)