Twenty miles off the coast of San Francisco, this small chain of islands hosts a yearly migration of seals… and during this time of year, the sharks are here too - the biggest, hungriest Great Whites in the world.Attempting to swim off these shores is attempted suicide.Colin Mason - wealthy, connected - with one leg bitten off by a white shark in these very same waters - now hosts his own yearly event - a marathon swim through the Great White-infested Farallons, The prize is a million dollars - winner takes all.How much is your life worth?