Berlin is still in saddened shock after the sudden death of Thomas Dörflein, the 44-year-old zookeeper who died suddenly Monday of a heart attack. A quiet man by nature, Dörflein was thrown into the spotlight after being chosen to raise the now-world-famous polar bear Knut by hand when the cub's mother rejected him.

PHOTO GALLERY: BERLIN MOURNS KNUT KEEPER THOMAS DÖRFLEIN

DPA

Berlin zookeeper Thomas Dörflein rose to worldwide fame along with his furry white charge, Knut the polar bear. News of Dörflein's sudden death on Sept. 22, 2008 triggered an outpouring of feeling from around the world. Here, visitors leave flowers and notes in Knut's enclosure.

DDP

Happier days: Young Knut plays with Dörflein. After the polar bear cub was abandoned by his mother, the zookeeper raised him by hand. Fans fell hard for the tiny polar bear during the daily "Knut show," during which the cub played games with Dörflein for a few hours everyday in front of huge crowds.

AP

The zoo also launched an online condolence book for Dörflein on their Web site on Sept. 25, 2008. A day later, there were already thousands of posts from around the world. Visitors were also leaving stuffed polar bears, flowers and candles in front of the entrance of the zoo in Berlin.

REUTERS

"You were our friend for too short a time," reads one of the letters taped to the zoo's entrance.

DPA

The Berlin Zoo announced Thursday they will award an annual Thomas Dörflein Prize beginning this June. The prize will award outstanding zookeepers with a trophy and €1,000. Pictured here is a sketch of the trophy.

AP

"Knut will go on looking for his keeper for a few days," zoo official Heiner Klös told the "Bild" daily Wednesday. "The bear has noticed that someone is no longer there."

The entrance to the Berlin Zoo is now choked with flowers, candles and stuffed animals -- polar bears, of course. The scene resembles the flower-strewn gates of London's Buckingham Palace in the wake of the 1997 death of Princess Diana.

"For a short time, you were a friend to us," reads one of the letters taped to the gate. Visitors have left a second heap of flowers inside the zoo in front of Knut's enclosure.

To honor Dörflein, the Berlin Zoo has set up a Web site on which people can post their condolences. Messages are now pouring in from all over Germany and the world. By Friday evening -- only a day after the site was launched -- it already had almost 7,000 posts. Most are from Germans, but zoo fans from countries across the globe -- including Vietnam, the United States, Turkey, the Netherlands, Sweden and France -- have also posted messages.

"I didn't know him personally," wrote Ellen Ertelt. "But the loving way he treated Knut and probably all animals was really wonderful."

The zoo has also set up a prize for outstanding zookeepers in Dörflein's honor. The first Thomas Dörflein Prize, which will carry a €1,000 ($1,460) purse as well as a trophy, will be awarded this June. When Knut was born in December 2006, he was abandoned by his mother. After his brother died four days later, the zoo decided to hand raise the cub, and Dörflein was assigned the job. The two quickly developed a very close bond, and their interaction became a zoo draw in its own right. Huge crowds of fans fell for the tiny polar bear during the daily "Knut show,"when the two would frolick around the bear's enclosure. Some visitors came to love Dörflein, too, an offbeat sex symbol with a bushy beard and ponytail.

"I have a pile of love letters from around the world on my desk. They're even sending me poems and songs they've written about me," Dörflein once told Berlin dailyDer Tagesspiegel. "It happens at least 20 times a day: I'll be walking somewhere, and people will shout 'Knuuut, Knuuut!'"

According to his colleagues, Dörflein was somewhat bewildered by all the attention. On Thursday, Zoo director Bernhard Blaskiewitz saluted Dörflein for remaining a "humble and modest man" despite global fame.

"Whether he wanted to or not, Thomas Dörflein made Berlin history in successfully raising