In 1978, Navy Commander John Collins dreamed up a race to settle a long-standing debate: who is fitter, the swimmers, runners or cyclists?
Australian Triathletes Greg Bennett (left) and Peter Robertson at the 2004 Athens Olympics.
He combined three existing races held in Hawaii, to be completed in succession: the Waikiki Roughwater Swim, the Around Oahu Bike Race (originally a two-day event) and the Honolulu Marathon.
"Whoever finishes first we'll call the iron man,'' Collins said.
Fifteen men took part in the first event. Twelve finished, led by Gordon Haller in the winning time of 11 hours, 46 minutes, 58 seconds.
Today triathlon is raced over distances including, 300m swim 10km bike, and 3km run for beginners, 750m/20km/5km, 1500m/40km/10km, 1.9km/90km/21.1km and 3.8km/180km/42.2km.
In 1989 the first Triathlon World Championship was held in Avignon, France, using the Olympic distance of 1500m swim, 40km bike and a 10km run.
This distance would be chosen for the Sydney Olympics in 2000, and for Triathlon's debut Commonwealth Games' debut at Manchester 2002.
In Previous Games
Canada dominated the Triathlon at the Manchester Games winning gold in both the Men's and Women's events.
Simon Whitfield took home the Commonwealth gold, with Australian Miles Stewart and Hamish Carter of New Zealand winning silver and bronze.
Carol Montgomery took the Women's gold, with Leanda Cave of Wales second and Nicole Hackett of Australia third.
At Melbourne 2006
The Triathlon will follow a loop course with a two lap swim, five lap cycle and two lap run. The distance of a 1500m swim 40km cycle and 10km run is the same as it was in Manchester.
It is classified as a technical course and for the first time in Triathlon the competitors in the cycle leg will be turning over tram tracks.
The roads in some instances are narrow and potentially could have runners and riders sharing the same space.
Again the bike leg will be draft legal, meaning the athletes can draft behind the cyclist in front of them.