The document provides information about the history and details of the Iditarod sled dog race in Alaska. It discusses how the race originated from a 1925 serum run to deliver diphtheria medicine to Nome by dog sled. It then gives an overview of the modern Iditarod race from Anchorage to Nome covering checkpoints and distances. It also describes the roles of mushers and dogs that make up the sled dog teams that compete in the challenging 1,049 mile race each year.