The 1925 serum run to Nome, also known as the Great Race of Mercy and The Serum Run, was a transport of diphtheria antitoxin by dog sled relay across the U.S. territory of Alaska by 20 mushers and about 150 sled dogs across 674 miles (1,085 km) in 5 ½ days, saving the small town of Nome and the surrounding communities from a developing epidemic of diphtheria.

Both the mushers and their dogs were portrayed as heroes in the newly popular medium of radio and received headline coverage in newspapers across the United States. Balto, the lead sled dog on the final stretch into Nome, became the most famous canine celebrity of the era after Rin Tin Tin, and his statue is a popular tourist attraction in both New York City's Central Park and downtown Anchorage, Alaska, but it was Togo's team which covered much of the most dangerous parts of the route and ran the farthest: Togo's team covered 260 miles (420 km) while Balto's team ran 55 miles (89 km). The publicity also helped spur an inoculation campaign in the U.S. which dramatically reduced the threat of the disease.