Born 1938, Whangarei, New Zealand

Modern polar exploration is usually a sophisticated undertaking. Adventurers travel by dogsleds or—more commonly—snowmobiles, and are often resupplied by airplanes throughout their journeys. Helen Thayer, an athlete and veteran outdoorswoman, developed a different sort of plan for traveling in the Arctic. In 1988 she journeyed to the North Magnetic Pole on foot and skis, taking only what provisions she could pull behind her on a sled. And the fifty-year-old adventurer traveled alone, except for a black husky dog named Charlie, whose sole purpose was to protect her from hungry polar bears. After a trying twenty-seven-day, 364-mile Arctic journey, Thayer succeeded in becoming the first woman to travel alone to either of the world’s magnetic poles.

Thayer began her life of high adventure early. She grew up on a large, hilly New Zealand farm where sheep and cattle...