Beaumaris Gaol

Reports here include: the sounds of "wailing", shuffling feet, disembodied voices and whispering; the sensation of being touched; sightings of shadowy figures and poltergeist activity. It is also reputed that a former jailer has been heard whistling, knocking on doors, and clinking his keys on the metal handrails as he does his rounds of the former prison.

Link: North Wales Live