They call it "The Last Great Race on Earth." The Iditarod Trail Sled Dog Race, commonly known as the Iditarod, is a race like no other.
It stretches more than a thousand miles across the Alaskan wilderness in winter, over two mountain ranges, down the Yukon River, and along the frozen Bering Sea.
The Iditarod, which began in 1973, has evolved into a grueling battle of highly competitive teams. The teams consist of one man or woman, known as a musher, up to 16 dogs, a sled, and of course the courage -- or craziness -- to attempt the incredible.
So, why do they do it?
Martin Buser, a four-time Iditarod champion, said his guess is as good as anyone's, as he fed dogs at a race checkpoint.
The race starts on the first Saturday of March every year in Anchorage, and the first musher usually reaches Nome, the endpoint, about nine days later.
Over all that distance it is clear that this is a team sport. And given all the hazards -- frostbite and falls, moose attacks, vicious weather, and thin ice in some years -- it should come as no surprise that more people have climbed Mount Everest in the last 35 years than have finished the Iditarod.
"I am bemoaning the fact that I've been lost for an hour and three quarters in this race already," said Jeff King, another four-time Iditarod champion, "in a race that could very well come down to minutes separating first and second."
This year, Lance Mackey, a cancer survivor who is the son and brother of previous champions, has taken the lead in the final days and is heading "home to Nome" tonight in an attempt to make history.
Just three weeks ago he and his team won the 1,000-mile Yukon quest dog race in record time.
A win tonight would make him the first musher to win both races in the same year, running a distance equal to that between Los Angeles and Atlanta.
"To me, they look like champions," Mackey said about his dogs as he entered Unalakleet, the first checkpoint in the Iditarod.
There are animal-rights activists who say this sport is cruel, and one dog has died on the trail this year. But to most Alaskans and fans around the world, the Iditarod is much more than a race.
It's a celebration of a way of life that has almost vanished on the last frontier, and a tribute to the ancient working partnership of man and beast.
"These dogs are just supreme athletes," said Stuart Nelson, chief veterinarian of the Iditarod race. "Almost unimaginable, the athletic ability these animals have."
Out on the trail, however, there is no time for debates. There's just the challenge, and the miles stretching into the timeless wilderness that is Alaska.