Built more than ten years ago on an abandoned Soviet military base in Germany at a cost of $110 million, the airship hangar seen above is the largest freestanding building in the world. Measuring more than 1,100 feet long and nearly 700 feet wide, the building was meant to serve as the construction site for a massive helium machine designed by entrepreneur Carl von Gablenz that would, he hoped, function as a delivery vehicle for oil rigs, wind turbines, and other industrial equipment. When von Gablenz's company ran out of money, a Malaysian firm bought the building and converted it into a huge water park that now sees nearly one million visitors annually.

The resort feature the world's largest indoor rainforest, which includes more than 50,000 trees; a swimming pool that is larger than four Olympic-sized pools together; 600 feet of faux beach; a nine-story waterslide; and other amenities. Read more about the Tropical Islands Resort, and the story behind von Gablenz's failed company, in the current issue of Air & Space magazine.



View more Pictures of the Day.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.