Thames Flood Barrier

The Thames Flood Barrier was a flood control structure on the River Thames.

On 25 December 2007 it was partially destroyed by the Tenth Doctor. He used explosives to blow up certain strategic points of the structure. This then allowed the entire contents of the Thames to enter the abandoned Torchwood Institute laboratory underneath, and flow to a hole in the middle of the secret base. This drowned the children of the Racnoss, who were emerging from this hole, which extended all the way to the centre the Earth. (DW: The Runaway Bride)

In an alternate timeline, the encounter between the Doctor and the Empress ended differently. Although she was still killed, the Doctor also died, leading to a chain of events that drastically altered Earth history. The Thames remained closed for over a year, resulting in a great number of financial problems for Britain as a whole as well as the locals who had to cross the Thames on a regular basis. (DW: Turn Left)