What event does the Iditarod race commemorate?

Answer 1

The serum run of 1925. The dogs were used to rush vaccine to Nome as the only airplanes available were open cockpit, had engines that were minimally functional in cold weather and in winter storage. The serum was passed along in a relay form team to team after being transported by train from Seward to the end of the line. The dog teams used the mail trail and completed the run in 5 days 7 hours and 30 minutes. The normal run time was 25 days.