Beaumaris Gaol

This grim, stout-walled jail, built in the early 19th century and largely unaltered since, was modern for its time, with toilets in every cell and a treadmill water pump. However, that's not enough to dispel the gloom of the windowless punishment cell, the cell where condemned prisoners awaited their demise at the gibbet, or the stone-breaking yard where inmates were subjected to hard labour. Since it closed as a jail it's been used as a children's clinic (cheery!) and a police station.