Coolest Pool ever. This is so what we need in the back yard. DISAPPEARING SWIMMING POOL-Watch this go from hidden to a wade pool to deep swimming pool and back up again to hidden. This is the coolest thing I have ever seen.
Natural Pools - Natural Swimming Pools and Ponds - The Daily Green - this page mentions converting an existing pool into a natural swimming pond by adding a shallow plant area around the original for natural purification.