8. Visit Dracula's Castle

Port: Bucharest, Romania

Explore 14th-century Bran Castle, which is intimately linked to the legend of Dracula. This fortress was used by Vlad the Impaler as a base for his forays into the Transylvanian countryside.

Who Offers It: Viking River Cruises and Avalon Waterways offer this three-day cruise extension (prices vary).