Berlin's beloved polar bear Knut, an international star who as a cuddly, fluffy cub graced magazine covers, movies and merchandise, died Saturday. His death at the young age of four took zookeepers and animal experts by surprise. The celebrity bear died suddenly in his compound at the Berlin Zoo on Saturday afternoon, bear keeper Heiner Kloes told The Associated Press. He waded into the water in his enclosure before having a short spasm and then dying in front of hundreds of zoo visitors.