Billionaire Richard Branson is a fearless, risk-taking entrepreneur. He founded and built the Virgin Group, a conglomerate that controls brands including Virgin Atlantic, Virgin Mobile, and Virgin Galactic.

Yet as an entrepreneur, he’s learned to discern between a calculated risk and a plain, dangerous one. A harrowing new documentary called “Don’t Look Down,” released today, shows how he learned that lesson.

The film chronicles the 31 hours in 1987 when Branson took on a potentially deadly challenge — crossing the Atlantic Ocean in a hot air balloon.

During his record-breaking journey of becoming the first to complete a transatlantic journey in a hot air balloon, Branson had a near-death experience. As he and his co-pilot tried to land the balloon in Scotland, they crashed into the ground, and the balloon bounced back over the Irish sea. The co-pilot jumped into the water but Branson stayed on and was lifted back into the clouds.

“I’d had an extraordinary life and it looked like this was the last two or three minutes of it,” Branson says in the documentary. “I wrote a note to the kids, telling them how much I loved them.”

Branson was rescued, and four years later, he completed a similar journey across the Pacific.

“If you’re an entrepreneur, the most important thing is to make sure that even if the worst thing happens, you’re not going to lose everything,” Branson says.

Watch our interview with Branson above to learn more.