13. Tropical Islands Resort – Krausnick, Germany

Set inside a repurposed airship hangar, Tropical Islands Resort is the world’s largest indoor water park—and it's seriously next level. Palm trees, a man-made beach, a sprawling 4,400-square-meter “Tropical Sea,” and even a rainforest create a full-blown tropical escape just an hour from Berlin. Perfect year-round, this resort is a tropical surprise in the heart of Europe.