Thames Flood Barrier

The Thames Barrier is a flood control structure on the River Thames. On 25th December 2007 it was destroyed by the Doctor to drown the children of the Racnoss, who were emerging from a hole drilled to the center of 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)