I took this shot in a pool with my brothers. It seems that ever since I can recall, the deciding factor of which hotel to stay at when my family and I went on vacation (other than price) was whether or not it had a pool. The deeper the better.
I chose this photo because it shows a view of water that we normally don't get to see. It also conveys a sense of this huge availability of water; we're swimming in it, using it for recreational purposes. Never mind the huge amount of chlorine and other chemicals that go into it, or how many thousands of gallons of freshwater are cycled through that thing every day. It just seems like a waste, especially if it's right by another source of swimmable water like a lake.
I have a waterproof digital camera that I used to take this. It's fantastic - you can even use it with a flash. I liked how the quick shutter speed captured the rising bubbles in this blue underworld.