This is hardly the definitive source of info about the Iditarod, but since nothing was posted here yet, I thought some folks might be interested.
"The world-famous Iditarod race commemorates the husky's finest moment. In the particularly harsh winter of 1925, a violent diphtheria epidemic broke out in the coastal city of Nome. The governor of Alaska ordered mushers to report to relay points along the 670 miles between Nenana and Nome to transport life-saving serum to the mortally threatened city. The legendary Serum Run involved twenty dog teams relaying serum along much of what is now the Iditarod trail. Out of this heroic mission arose the legends of Togo and Balto, two lead dogs who pulled their sleds through blanketing whiteouts, one of whom—Balto—is honored with a bronze statue in New York's Central Park." And a goofy movie. —Merrily Weisbord and Kim Kachanoff, Dogs with Jobs: Working Dogs Around the World (NY and London: Pocket Books, 2000), 155