The Thames Flood Barrier, or Thames Barrier, (AUDIO: Traitors' Gate) was a flood control structure located on a 520-metre-wide stretch of the River Thames, between Newham and Greenwich, in London. (PROSE: The Time Traveller's Almanac [+]Loading...{"chaptname":"Everything Changes","page":"104","chaptnum":"3","1":"The Time Traveller's Almanac (reference book)"}) It was cited by Donna Noble as a major London landmark. (TV: The Runaway Bride)
The Thames Barrier was constructed between 1974 and 1984 and consisted of ten movable gates, positioned end-to-end across London's River Thames. These gates could seal the river off from the sea in the event of dangerously high tides. The four largest gates were 20 metres tall and weighed roughly 3700 tonnes. (PROSE: The Time Traveller's Almanac [+]Loading...{"chaptname":"Everything Changes","page":"104","chaptnum":"3","1":"The Time Traveller's Almanac (reference book)"})
On 24 December 2007, it was partially destroyed by the Tenth Doctor. He used explosives to blow up strategic points of the structure. This let the Thames flood the abandoned Torchwood Institute laboratory underneath and flow to a hole in the middle of the secret base. This hole extended all the way to the centre of the Earth. The river water drowned the children of the Racnoss, who were emerging from the hole. (TV: The Runaway Bride)
In a parallel world, while the Doctor still killed the Racnoss' children, he also perished in the flooding. (TV: Turn Left)