I am a huge fan of swimming. It is one of the most recognized recreational activities in the world.
I don't consider myself a strong swimmer, but I do enjoy it very much!
Do you ever swim in built into the ground or above ground pools?
Every weekend! My parents have an in ground pool. We enjoy it very much, so relaxing!
It is relaxing! I really enjoy floating on the surface to relax. Our body density allows us to do this.
Yes, one of the very first things they teach in swim lessons is how to float on your back! 
Body fat and the amount of salt in the water also dictate how easy you can float. Not everyone can enjoy it.