The Iditarod is an annual sled dog race that takes place in Alaska. It is a long-distance race that covers over 1, 000 miles of the Alaskan wilderness. The race usually starts in Anchorage and ends in Nome, and it is considered one of the most challenging and grueling races in the world. The race is held in honor of the 1925 serum run to Nome, which was a relay of dog sled teams that delivered diphtheria antitoxin to the town of Nome.