Knut the polar bear was a star at the Berlin Zoo despite a rough start in life. As a cub, he was abandoned by his mother, but a zookeeper hand-raised him to adulthood. <a href="http://www.cnn.com/2011/WORLD/europe/03/21/germany.knut.dies/">His death of encephalitis in 2011</a>, when he was 4, shocked fans. "Knut was something very special," said a zoo board member.