Where I live, Dumbarton, we had a castle. It dates right back, and is fortified. Sits on Dumbarton Rock, and Mary Queen of Scots stayed there before she was taken to France for safety. Then there is almost no-where that doesn't have some Mary Queen of Scots conections.

On the Lake of Menteath, there is a ruined Abbey that you can take a boat over to (it is lovely, the island has a feeling of quiet and serenity about it) and take a walk and/or explore the ruins!