I've seen some pretty large and unique pools in my life, but  this one takes the prize by a large margin

"The Mountain" was built in Springville, Utah for someone who loves the mountains, but is also an avid scuba diver. Made out of an obscene amount of rebar, steel beams, and concrete, this monster has 5 waterfalls, a hidden slide, full kitchen, and a secret entrance to a place to scuba dive.

Someday... I'll have to build a better one!