"Dungeon" is a corruption of donjon,
the French term for tower. Contrary to popular belief of the
dank, dark basement pit, most prisoners were held in the castle's
highest tower, passage to which was guarded by soldiers. Basement
or pit dungeons did exist with famous prisoners immortalized
For six years Francois Bonivard was chained to a pillar in
Switzerland's Château Chillon, near Montreux.
In the early 1800s, romantic poet Lord Byron spent a night
in the dungeon and wrote The Prisoner of Chillon.
His name can still be seen carved into the third pillar.
The Château d'If near Marseille, France was
the setting where Alexandre Dumas père's fictional
character ... escaped to become The Count of Monte Cristo.
Medieval castles' stone walls, narrow windows and limited
access points led many to be converted into prisons. The Tower
of London and Paris' Bastille housed many political prisoners
over the years.