If you are a professional diver you should visit Cenote Angelita, Mexico. There's some kind of cave. When you go deeper than 30 meters the water is fresh, deeper than 60 - it's salty. And then you see a river underneath, with trees and leaves. But of course, it's not a real river. It's just a layer of hydrogen sulphide. But it looks amazing. [Via http://acidcow.com/pics/5546-underwater-river-in-mexico-4-pics-video.html]


