Staying alive against the odds is nothing new, but learn how to survive a swimmer's worst fear. Amateur shark enthusiasts dive into the warm waters of the Caribbean to find out just how easy it is to wind up on the menu. Northeastern Australia boasts the world's largest concentration of sharks, but find out why that may be changing. Return to the water to take a bite out of some of the better-known shark myths. Whenever swimmers get into the ocean, they enter the domain of sharks, so learn what happens when victims break a few simple shark rules. Go ice-fishing in Canada's frigid far north to find what may be the world's most mysterious shark.