Nobody likes to swim in a dirty pool. Personally, I don't like swimming in lakes, streams, or any body of water where you can't see the bottom. (How would you know if you're swimming in something gross?) If you're a germaphobe, there is one lake where you needn't worry about swimming in something diseased or slimy. That's because this lake is so irradiated, every germ in it is probably dead.Lake Karachay in the Urul Mountains is so polluted with nuclear waste that merely standing next to it for an hour will give you a dose of 600 roentgen (which is...