For the new Triathlete it’s always good to understand to roots of your sport.
Triathlon as we know it today (swim, bike, run) is a relatively new sport and originated in San Diego in 1974. I lived their for years and had no idea and not that I’m hooked on the sport I took the opportunity to get a photo of the spot. Triathlon.org as a very good write-up on the history at the following link. Birthplace of Triathlon