In 2010, eccentric millionaire Forrest Fenn launched a treasure hunt when he announced that he had hidden a chest worth an estimated $1 million in the Rocky Mountains. Tens of thousands of people set out to search for the treasure — some of them obsessively.

Sacha Dent was captivated by Fenn’s challenge. “I really think the greatest thing that drove me was wanting to match wits with the man himself,” she says of Fenn, who laid out his treasure hunt challenge in a 24-line poem.

“CBS This Morning” co-host Tony Dokoupil wrote an article about Fenn’s treasure in 2012 for Newsweek magazine. That article is widely credited with introducing Fenn’s modern-day treasure hunt to a national audience.

“I think a lot of people really wanted to be part of something bigger than themselves … maybe there was something missing in their lives,” journalist Dan Barbarisi tells Dokoupil. “And for others it was that they felt that people hadn’t believed in them to the extent that they should have.”

To some, Fenn was a hero, providing a way to instant wealth and adventure in the great outdoors through the treasure hunt. To others, he was reckless and cost lives. Five people ultimately lost their lives in the process.

“He didn’t like the idea that anyone would tell him to bring his hunt to an end because of a few deaths,” Barbarisi says of Fenn. “He said that if somebody was murdered because of the hunt that would probably be too much.”