Triathlon is a subtopic of Adventure. See Adventure's other subtopics and posts.
Triathlon is unique because it requires skill and mental toughness in multiple disciplines, along with money, gear, and time. One of my proudest moments in sports was emerging from Lake Coeur d’Alene in my first Ironman, having successfully swam 2.4 miles for the first time in my life. Never mind there were still 112 miles to bike and 26.2 miles to run — sometimes the greatest thrills are from conquering weaknesses.