Sweden was literally born of the sea. The Stockholm Archipelago comprises thousands of islands, 14 of which form the country’s spired-crowned capital, Stockholm. The “city that floats on water” is featured on numerous Holland America Line cruises, and you’ll find an equal number of ways to experience it (RIB boat adventure, anyone?). The fortified medieval city of Visby is a UNESCO World Heritage Site and your entrée to bucolic farms and Bronze Age ruins on Gotland, Sweden’s largest island.