Myths and mysteries swirl around the Thames like the eddies around the renowned bridges over the river. Some are true, some are half true, some are piffle. Many are grisly.
But how sure are you of the ones you reckon are true? That tale about pigs in the sewer system, living off scraps washed down sinks and from slaughterhouses — that's got to have credence, right? Queen Rat, on the other hand...
Scott Wood, host of the London Fortean Society, has been collecting myths, mysteries and barely-believable true tales about the river for years.
"There's long been held the belief that London Bridge is a site of child sacrifice," he says. "There's a Bronze Age burial site by the bridge and there are a number of graveyards close by. It's led people to think that the site was one of child sacrifice — orphans being put into the bridge as a way of protecting it.
"Further strength has been given to the story, based on the nursery rhyme London Bridge Is Falling Down, which describes ways the bridge is built and rebuilt using different materials, including the verse, 'set a man to watch all night, watch all night, watch all night'. Some people have speculated that this is a euphemism for human sacrifice."
There's also the tale of pigs in the sewers, based on a report from before the river Fleet — which flows into the Thames — was bricked over to become part of the city's sewage system.
The tale goes that back when live animals would be taken to Smithfield Market for slaughter, a worker at the site lost a pig into the Fleet Ditch, only to find it months later, fatter than when he lost it. Apparently it had been living on the scraps in the ditch. Once the ditch was built over to create the city's sewage system, stories have abounded that pigs got into the system from the fields of Hampstead, and have been breeding down there, feeding off the city's waste.
"Where the sewer pig story comes from is a book called London Labour and the London Poor, by Henry Mahew, published in the 1850s," says Wood. "He went around the city interviewing the poor — and describing his findings and interviews.
"However, it seems some sewer workers, spotting he was somewhat naïve, spun him the yarn about pigs in the sewer system, and he fell for it."