In 1976, RiverCountry opened up at Walt Disney World in Florida. By 2001, it had closed. Now, it stands–rotting and decrepit in a manner that J.G. Ballard would have approved of. These photos come from an excellent thread about River Country on Dis Boards.
It was just a waterpark, although one of the first generation of waterparks. Here are the rotting water slides:
Some fake rocks:
And a map of the whole sorry affair: