Will Dean is the founder and CEO of Tough Mudder, the world’s most successful endurance event. Will first came up with the idea for the race while studying for an MBA at Harvard, and despite the protestations of his professors, he decided to put his dream to the test. He’d hoped to get 500 participants to his first ever event — in the end, he got more than 5000.

In just the seven short years since, Tough Mudder has gone from strength to strength, and today has put more than 2 million people through their paces at 150 events worldwide.

In this episode, Will tells us how close he came to tear gassing his participants, why he imported mud into the desert, and how his flash of inspiration came at the hands of an ill-fitting wetsuit.