Allan Savory isn’t afraid to own up to the “greatest blunder” of his life. In his incredible talk from TED2013, Savory shares his life’s work managing grasslands in Africa, weaving a gripping tale out of what seems like an unlikely topic. Allan Savory: How to fight desertification and reverse climate change In the 1950s, Savory helped create large national parks in Africa. But as people left this land to make way for animal reserves, Savory and his team noticed the land deteriorating and quickly turning into desert. After careful analysis, they determined that the problem was an over-abundance of elephants. And so in a politically heated move, they shot 40,000 elephants in order to save the grasslands.

Only, it didn’t work. Even with all these elephants killed, the grassland deterioration only got worse. In a powerful moment in the talk, Savory expresses his dismay.

“That was the saddest and greatest blunder of my life,” he said. “I will carry that to my grave.”

To hear how Savory, over the next few decades, found real solutions to the problem of desertification — one that involves livestock — watch his talk. Here, other bold speakers who’ve owned up to mistakes or expressed what they’ve learned from failure.

• Richard St. John: “Success is a continuous journey”
• Kathryn Schulz: Don’t regret regret
• JK Rowling: The fringe benefits of failure
• Tim Harford: Trial, error and the God complex
• Diana Laufenberg: How to learn from mistakes
• Kathryn Schulz: On being wrong
• Michael Litt: Why you need to fail to have a good career