London Bridge was a London structure near the Houses of Parliament that crossed the River Thames.
In the 15th century, it had houses and shops on it, but these were gone by the 20th century. In 1400, it was adorned with the heads of the Duke of Huntingdon and the Duke of Gloucester. Someone had put an apple in the mouth of the latter. (AUDIO: The Doctor's Tale)
In 1605, the Eleventh Doctor retrieved a piece of fuse wire at the bottom of the bridge for Guy Fawkes as part of an errand to gain the trust of the plotters of the Gunpowder Plot. Later, Robert Catesby outlined the final preparations for the plot inside the Duck and Drake. At the same time, Amy Pond and Rory Williams found power rods for Lady Winters' ship on the bridge. (GAME: The Gunpowder Plot)