It's a bitterly cold winter day and students on the University of Minnesota campus are bundled up, hurrying to their next class. Wim Hof, dressed in shorts, sandals and nothing else, appeared from the doorway of a school building.
He's known as 'The Ice Man."
Scientists can't really explain it, but the 48-year-old Dutchman is able to withstand, and even thrive, in temperatures that could be fatal to the average person.
It's an ability he discovered in himself as a young man 20 years ago.
"I had a stroll like this in the park with somebody and I saw the ice and I thought, what would happen if I go in there. I was really attracted to it. I went in, got rid of my clothes. Thirty seconds I was in," Hof said. "Tremendous good feeling when I came out and since then, I repeated it every day."
It was the moment that Hof knew that his body was different somehow: He was able to withstand fatally freezing temperatures.
Hof began a lifelong quest to see just how far his abilities would take him. In January of 1999 he traveled 100 miles north of the Arctic Circle to run a half-marathon in his bare feet. Three years later, dressed only in a swimsuit, he dove under the ice at the North Pole and earned a Guinness World Record for the longest amount of time swimming under the ice: 80 meters, almost twice the length of an Olympic-sized pool.
When he didn't experience frostbite or hypothermia, the body's usual reactions to extreme cold, his extraordinary ability started to get the attention of doctors who specialize in extreme medicine.
Dr. Ken Kamler, author of "Surviving the Extremes," has treated dozens of people who tried to climb Mount Everest, and instead nearly died from the frigid temperatures. He couldn't believe it when he got word of a Dutchman making the ascent with no protection other than a pair of shorts.
"People are always looking for new firsts on Everest. It's been climbed so many times now, people climb it without oxygen, they … they climb it with all different kinds of handicaps. But no one has come close to climbing Everest in those kinds of conditions," Dr. Kamler said. "It's … it's almost inconceivable."
Hof made the expedition in shorts.
"It was quite easy," Hof said. "I was in a snowstorm before, say, on the fifteen, sixteen thousand feet up 'til eighteen thousand feet."
"I know my body, I know my mind, I know what I can do," Hof said. And he says he can withstand heat as well as cold.
Dr. Kamler met Hof for the first time at the Rubin Museum in New York, where Hof was set to break another Guinness World Record, this time for remaining nearly naked in ice poured up to his neck.
Hof came out of the museum, stripped to his swim trunks and climbed in a 5-foot tall plexiglass container filled with ice. Once he got in, they poured more ice into the container until it reached his chin.
All the while, Dr. Ken Kamler monitored Hof from outside the tank.
Normally, when a person is exposed to freezing temperatures for a prolonged period of time, the body goes into survival mode, as its liquids begin to freeze.