River Fleet
From Tardis Wiki, the free Doctor Who reference
The River Fleet was a largely underground river that emptied into the River Thames at Blackfriars Bridge in London. (TV: The Talons of Weng-Chiang) Like many of London's underground rivers, it had been buried by the builders of what George Litefoot termed "the spreading metropolis". (AUDIO: The Ruthven Inheritance)
The Fourth Doctor knew its exact course, as he had once caught a salmon there with the Venerable Bede. (TV: The Talons of Weng-Chiang)
The Eighth Doctor later commented that, of all London's subterranean rivers, the Fleet was the one most associated with evil. (AUDIO: Dead London)
