Behind the abbey is Stirling Castle. This is one of Scotland's two most important castles (the other being Edinburgh). Stirling was central to the battles of the first Scottish war of independence, with the Battle of Bannockburn in 1314 being fought nearby. If you haven't been to the area, Stirling is a great town to visit; it has huge historical interest due to its centrality in many of these battles, it is easy to get to Glasgow and Edinburgh from and it is a "gateway" between the industrial Central Lowlands of Scotland and the more rural Highlands.
Well worth a visit next time you're in the UK!