Wife really wants to go to Scotland, I'd love to go too, but wouldn't go for less than 3 weeks if I did. Can't afford it these days, but on the back burner for now.
Edinburgh Castle is really nice as well. The big cannon is called The Mons Meg. The shot weighed in around 350 lbs and could shoot one hell of a distance. They could only fire it several times then had to let the barrel cool down. Google it.