The children of Nome were dying in January 1925. Infected with diphtheria, they wheezed and gasped for air, and every day brought a new case of the lethal respiratory disease. Nome’s lone physician, Dr. Curtis Welch, feared an epidemic that could put the entire village of 1,400 at risk. He ordered a quarantine but knew that only an antitoxin serum could ward off the fast-spreading disease.

The nearest batch of the life-saving medicine, however, rested more than 1,000 miles away in Anchorage. Nome’s ice-choked harbor made sea transport impossible, and open-cockpit airplanes could not fly in Alaska’s subzero temperatures. With the nearest train station nearly 700 miles away in Nenana, canine power offered Nome its best hope for a speedy delivery.

Sled dogs regularly beat Alaska’s snowy trails to deliver mail, and the territory’s governor, Scott C. Bone, recruited the best drivers and dog teams to stage a round-the-clock relay to transport the serum from Nenana to Nome. On the night of January 27, 1925, a train whistle pierced Nenana’s stillness as it arrived with the precious cargo—a 20-pound package of serum wrapped in protective fur. Musher “Wild Bill” Shannon tied the parcel to his sled. As he gave the signal, the paws of Shannon’s nine malamutes pounded the snow-packed trail on the first steps of a 674-mile “Great Race of Mercy” through rugged wilderness, across frozen waterways and over treeless tundra.

Even by Alaskan standards, this winter night packed extra bite, with temperatures plummeting to 60 degrees below zero Fahrenheit. Although every second was precious as the number of confirmed cases in Nome mounted, Shannon knew he needed to control his speed. If his dogs ran too fast and breathed too deeply in such frigid conditions, they could frost their lungs and die of exposure. Although Shannon ran next to the sled to raise his own body temperature, he still developed hypothermia and frostbite on the 52-mile leg to Tolovana before handing off the serum to the second dog team.

With moonlight and even the northern lights illuminating the dark Alaskan winter days, the relay raced at an average speed of six miles per hour. While each leg averaged 30 miles, the country’s most famous musher, Norwegian-born Leonhard Seppala, departed Shaktoolik on January 31 on an epic 91-mile leg. Having already rushed 170 miles from Nome to intercept the relay, Seppala decided on a risky shortcut over the frozen Norton Sound in the teeth of a gale that dropped wind chills to 85 degrees below zero. Seppala’s lead dog, 12-year-old Siberian Husky Togo, had logged tens of thousands of miles, but none as important as these. Togo and his 19 fellow dogs struggled for traction on Norton Sound’s glassy skin, and the fierce winds threatened to break apart the ice and send the team adrift to sea. The team made it safely to the coastline only hours before the ice cracked. Gusts continued to batter the team as it hugged the coastline before meeting the next musher, Charlie Olson, who after 25 miles handed off the serum to Gunnar Kaasen for the scheduled second-to-last leg of the relay.

Statue of Balto in New York’s Central Park (Credit: Getty Images)

As Kaasen set off into a blizzard, the pelting snow grew so fierce that his squinting eyes could not see any of his team, let alone his trusted lead dog, Balto. On loan from Seppala’s kennel, Balto relied on scent, rather than sight, to lead the 13-dog team over the beaten trail as ice began to crust the long hairs of his brown coat. Suddenly, a massive gust upwards of 80 miles per hour flipped the sled and launched the antidote into a snow bank. Panic coursed through Kaasen’s frostbitten body as he tore off his mitts and rummaged through the snow with his numb hands before locating the serum.

Kaasen arrived in Port Safety in the early morning hours of February 2, but when the next team was not ready to leave, the driver decided to forge on to Nome himself. After covering 53 miles, Balto was the first sign of Nome’s salvation as the sled dogs yipped and yapped down Front Street at 5:30 A.M. to deliver the valuable package to Dr. Welch.

The relay had taken five-and-a-half days, cutting the previous speed record nearly in half. Four dogs died from exposure, giving their lives so that others could live. Three weeks after injecting the residents of Nome, Dr. Crosby lifted the quarantine.

Although more than 150 dogs and 20 drivers participated in the relay, it was the canine that led the final miles that became a media superstar. Within weeks, Balto was inked to a Hollywood contract to star in a 30-minute film, “Balto’s Race to Nome.” After a nine-month vaudeville tour, Balto was present in December 1925 as a bronze statue of his likeness was unveiled in New York’s Central Park.

Seppala and his Siberians also toured the country and even appeared in an advertising campaign for Lucky Strike cigarettes, but the famous driver resented the glory lavished on Balto at the expense of Togo, who had guided the relay’s longest and most arduous stretch. “It was almost more than I could bear when the ‘newspaper dog’ Balto received a statue for his ‘glorious achievements,’” Seppala remarked.

The serum run was Togo’s last long-distance feat. He died in 1929, and his preserved body is on view at the Iditarod Trail Sled Dog Race Headquarters in Wasilla, Alaska. After the limelight faded, Balto lived out his final days at the Cleveland Zoo, and his body is on display at the Cleveland Natural History Museum. Since 1973, the memory of the serum run has lived on in the Iditarod Trail Sled Dog Race, which is held each March and is run on some of the same trails beaten by Balto, Togo and dozens of other sled dogs in a furious race against time nearly 90 years ago.