Dumbarton Castle Aka Dùn Breatainn, has the longest recorded history of any stronghold in Scotland. It sits on a volcanic plug of basalt known as Dumbarton Rock & overlooks the town of Dumbarton on the river Clyde. Visit the royal refuge that stood at the heart of an ancient kingdom covering the area now known as Strathclyde. Climb the White Tower Crag for stunning views as far as the peak of Ben Lomond Take in the artillery fortifications to see fine examples of early 18th-century military arch