For hearty participants in Chester County’s annual Tough Mudder, it’s survival of the fittest—on cherished land.

Business Insider spoke with CEO and founder of Tough Mudder Will Dean, about why people repeatedly come back to tackle the famous obstacle course. He said: "We are a tribe, a community.

The Fough Tudder Muckers attempt to overcome the Water Pit obstacle during the 2011 SoCal Tough Mudder in Big Bear Lake, CA. Mudders wade through the cold waters going under and over the obstacle ...

Around 18,000 people are expected to take part in a Tough Mudder event near Henley this weekend. The endurance test will take place at Culden Faw Estate in Greenlands on Saturday and Sunday, May 10 ...

Today, Tough Mudder announced a list of new obstacles and challenges that would be added in 2017, which are sure to recruit a new band of die-hard competitors as well as welcoming back old hands.