Brent Weigner

Brent Weigner is a mild-mannered, 57-year-old geography teacher, but when he laces up his running shoes, he turns into a warrior.

He has run ultra-marathons on every continent on the planet, which has taken him to nearly 100 countries and to the North Pole for races. Ultra-marathons involve distances of 26 miles or more and many of them are 100 miles long.

He says during ultra-marathons, he experiences everything from the depths of despair to the peaks of the mountaintops.

Find out how the lessons he's learned while running have translated to his life.