Dave Guertin finishes Ironman Mont-Tremblant, Quebec, Canada

During an awards banquet for the Waikiki Swim Club, John Collins, a Naval Officer stationed in Hawaii, and his wife Judy, began playing with the idea of combining the three toughest endurance races on the island into one race.

They decided to issue a challenge to see who the toughest athletes were: swimmers, bikers, or runners. On February 18, 1978, 15 competitors, including Collins, came to the shores of Waikiki to take on the first-ever IRONMAN challenge.

Official Ironman site...