Heidi Klum Swims with Sharks!

(F. Scott Schafer)

She's conquered the runway and the airwaves, but the most ambitious thing Heidi Klum's ever done doesn't involve fashion.

"I jumped into the water with 45 sharks without a cage in the Bahamas for a Discovery Channel show," the supermodel tells Parade.com. "That was a really good experience."

Not to mention fearless -- splashing around with sharks proved to be an epiphany for the 35-year-old.

"I'm not saying that everyone should swim with sharks, but sometimes you have to jump over your own shadow in order to learn something that you will never forget for the rest of your life," she says. "Then you know you can conquer your fears."

Meanwhile, 16 new contestants must conquer the runway under Heidi's watchful eye next week. The fifth season of Project Runway premieres Wednesday and the German-born babe is looking forward to telling people who's in and who's out -- even if it means breaking some hearts.

"It's tough not to be a winner," she says. "I always think back to when I won my first modeling competition in Germany. I was 18 and I just had to get out there and try hard. You've got to keep going and not give up. That's what I advise the designers who are on the show."

Still, an auf-ing shouldn't be taken personally.

"But I don't think that I'm mean to the contestants or do things to cause them any pain. I value honesty and I think they do too."