Ah, now this looks intresting. Apparently at some point during the 12th centuray a bunce of people were executed by maybe being forced to jump down a well, leaving a massive pile for us to find. But it is shrouded in mystery, apparently they were persecuted because they were jewish but could there have been another reason? A nice bit of loopy medieval logic here.
http://www.bbc.co.uk/news/uk-13855238
