Kilmainham Gaol ~ Dublin, Ireland
Kilmainham Gaol is a prison that was founded in 1796 and held many of the Irish revolutionaries fighting for independence so this place is full of history. Anyone with a drop of Irish blood in them will appreciate seeing this place. Even if you're not Irish - the history and architecture is worth a visit on it's own. The jail is located in downtown Dublin, so it's just a walk or a quick cab ride away. Tickets are cheap (€10 at the door), but I definitely recommend booking online in advance. That way you guarantee yourself a ticket and you also save yourself €1.
**See my full Ireland itinerary here.