I heard that the Ironman Triathlon competition was being held in nearby Tempe today, so I had to have a look.
I remember watching highlights from the Ironman in Hawaii on ABC’s Wide World of Sports when I was a kid. The graphic images stick with me today of people crossing the finish line and having virtually no control over their muscles after a day of grueling exercise consisting of a 2-mile swim followed by a 112-mile bike ride, followed by a 26.2 run (i.e. marathon). Today I witnessed it in person.
The Tempe course is great for spectators because you can see the athletes at numerous points in their journey, such as the start and end of the swim and bike ride, plus the run portion at the 4-, 12- and 26 mile points. Hat’s off to these amazingly driven individuals.
Here are some photos I took. Plenty more of professional quality at http://www.ironman.com.
Paul Fiarkoski 
It is amazing the extent a person can go to accomplish this. Bravo to all.