Many water parks have the ability to stay open year-round and are not affected by wind and rain. America’s indoor water parks love to make claims about being the biggest or even the world’s largest to attract new customers. But only a few can be among the largest indoor water parks in the world. To compare these resorts, we must look at the square footage of the indoor water park under one roof. This is a rapidly evolving industry, and new indoor water parks are constantly popping up while old ones are expanding. 1. Tropical Islands Resort, Krausnick, Germany. 710,000 sq ft Located in Krausnick, Germany, the Tropical Islands Resort is the largest indoor water park in the world. The water park is inside a 351 ft high hangar that stands as the world’s largest single hall without supporting pillars inside. Named Aerium, the structure was originally built as a zeppelin hangar but the airship it was intended to house was never built. A Malaysian company bought the hangar and turned into