Some friends of ours always have a big pool party every summer. Their backyard is big enough for the pool, a patio area yet still has some green space.  Every time I mow the lawn in our backyard, I wonder if our yard would be big enough to have a pool. (Okay, first our checking account would need to be big enough for us to afford to put in a pool, but still...) I always thought a pool might take up too much space. But that was before I saw this video. Check out these amazing hidden pools -- that let you enjoy the water, but also allow you to use the space when you're dry!