Here is one of my draining trips in London (mind you I didn't do many of them and this was my first and soon after I lost interests).
I arrived a bit late to find out that I am a “last minute addition” (even if I was invited to come). Oh well, nothing to be bothered about, soon after that trip I couldn't care less. But anyway a truly worth visiting place, a long, long walk and some cute rats, that's what I remember from river Fleet.
Here is a bit of history - already covered by adders:)
River Fleet is one of London's lost rivers, which once flowed from Hampstead to Blackfriars. Although long bricked over (as part of Joseph Bazalgette's monumental tunnelling programme during the 1860s and 1870s), the Fleet, like many of London's old rivers, still flows underground through a series of pipes and culverts. The Fleet River today is a huge underworld cavern of Victorian brickwork and London history. Though it has been changed and redirected, the river has never stopped running, rushing unseen, just beneath the sidewalks of London.(borrowed)
Some pics here:
For more information and better quality pics you can visit Silent UK site, well known as one of the best drainers in LDN - River Fleet.