John Albert Thompson was tending a ranch in the Sacramento Valley in 1856 when he heard that settlers in nearby Placerville were having difficulty getting mail to western Nevada during the winter months — when the Sierra Nevada filled up with snow, the journey seemed impossible.

Thompson had learned cross-country skiing in his native Norway and volunteered to make the trip. He proved so able that “Snowshoe Thompson” served as a one-man delivery service for the next 20 years. Carrying an 80-pound mailbag on his back and holding a pole for balance, he would typically make the 110-mile outbound trek in three days and return in two, subsisting on biscuits, dried meat, and snow.

“If I have my mackinaw,” he said, “I never freeze. Exercise keeps me warm. In fact, my problem even in blizzards is not to keep from freezing, but rather that I sweat too easily. I have never been cold in the mountains.” His sense of direction was unerring, and he regularly saved the lives of others who had become lost in the mountain passes. He died in 1876 after two decades of service, for which he was never paid.