There's nothing quite like cooling off in a nice pool on a hot summer day, but if that pool isn't clean, you can face all kinds of nasty diseases. And I'm not talking about a pool having enough chlorine, I'm talking about public pools where stranger's fecal matter contaminates every drop of water.
Don't believe me? You may never want to enter the water again after you read about all the diseases you can catch in a pool. On the upside, most just result in some diarrhea. On the down side -diarrhea.