This supermassive airship hangar(1,181 feet long x 688 feet wide x 351 feet high, big enough to hold 14 Boeing 747s) built a decade ago at an abandoned Soviet military base south of Berlin. Now it has been given a second life as an tropical islands resort that holds the world’s largest indoor pool and water park.

A waterpark is an amusement park that features waterplay areas, such as water slides, splash pads, spraygrounds (water playgrounds), lazy rivers, or other recreational bathing, swimming, and barefooting environments. Waterparks in more current states of development may also be equipped with some type of artificial surfing or bodyboarding environment such as a wave pool or a FlowRider.

Waterparks have grown in popularity since their introduction in the late 1940s. The United States has the largest and most concentrated waterpark market, with over a thousand waterparks and dozens of new parks opening each year. Major organizations are IAAPA (International Association of Amusement Parks and Attractions) and WWA (World Waterpark Association).