Do you remember Knut, the sweet polar bear cub that's been handraised in the zoo of Berlin in 2007? He was all over the media those days.

His life changed drastically when his beloved animal keeper, Thomas Doerflein, died from a heart attack when Knut was two years old. Knut was so lonely and sad in his last years. Now he followed his beloved friend...

R.I.P. sweet Knut!

Star polar bear Knut found dead