At the mouth of the Dart River, this ancient seaport is home of the Royal Naval College. Traditionally linked to England's maritime greatness, Dartmouth sent out the young midshipmen who saw to it that "Britannia ruled the waves." You can take a river steamer up the Dart to Totnes (book at the kiosk at the harbor); the scenery along the way is panoramic, as the Dart is Devon's most beautiful river. Dartmouth's 15th-century castle was built during the reign of Edward IV. The town's most noted architectural feature is the Butter Walk, which lies below Tudor houses. A Flemish influence, acquired through trade during the Middle Ages, is pronounced in some of the houses.