S19·E6 Polar Bear Invasion

Each October, the remote Canadian town of Churchill in Manitoba plays host to some very unusual guests. More than a thousand hungry polar bears gather there to await the refreezing of Hudson Bay and then move out on the ice in pursuit of their traditional winter diet of seal. The world's largest land carnivore, polar bears can be very dangerous for humans as well as sea creatures -- but for tiny Churchill, they also are a tourist-dollar bonanza.