In January 1925, doctors realized that a diphtheria epidemic was likely to sweep through Nome's young people. It could kill many people. The only serum that could stop it was in Anchorage. Anchorage was almost away. The only aircraft that could get the medicine to Nome was taken out of winter storage, but its engine was frozen. It would not start. Officials chose to move the medicine by sled dog. The serum was transported by train from Anchorage to Nenana. At Nenana the first "musher" began the trip as part of a relay to deliver the serum to Nome. More than 20 mushers took part. They had to deal with a blizzard with temperatures and strong winds. News coverage of the race was worldwide.