A couple of years ago I had to stop running due hip issues and started open water swimming instead! Today I revisited one of my favourite running routes - Riverside Country Park - a coastal path that runs alongside the River Medway Estuary. Jutting out from the path is a causeway leading to Horrid Hill which used to be a tiny "island" and reputedly gets its name from the prison ships moored nearby; any prisoners that tried to escape to the island (before a causeway was built) were hanged. There are other, alternative stories about the origin of the name. Magwitch from Charles Dicken's Great Expectations was one of these prisoners.
The last vessel to berth there, a barge named the Dick Turpin, ran aground nearby in 1913. Among the products it was carrying were jars of Dundee marmalade, examples of which (it is said) can still be found buried in the mud. I have never found any!