On June 27, 1999, spinning two and a half times in the air above a halfpipe on Pier 30 in San Francisco, Tony Hawk made history as he became the first skater to land the 900, the holy grail of professional skateboarding.

When Hawk landed the trick, a two-and-a-half revolution aerial spin completed on a vertical ramp, during the 1999 X Games, he won the gold medal for best trick and became the most famous skateboarder alive. The moment, which took Hawk 11 tries, is considered by some to be one of greatest feats in sports history.

Completing the 900 was the end of a decade-long quest, Hawk says, during which he lost several teeth, broke ribs, and suffered multiple concussions. Shortly after Hawk landed the trick, he retired from competition after 17 years to focus on his skateboard company Birdhouse and his other ventures.

Hawk says the seed of his quest was planted in 1985 while at a skate camp near Stockholm, which had the biggest ramp in the world at the time.

The ramp, Hawk says, allowed skaters to catch air for longer, which made it easier to pull off a trick.

After learning how to do a 720, his mind drifted. "The idea, at that point, was: What's next? The 900 was next," says Hawk, in an interview after a recent panel discussion at the American Express Success Makers Summit.

Hawk says he mapped out his goals as an athlete and he put the 900 on top of the list. He says he didn't focus solely on the 900, but he learned and created other tricks, which he says eventually helped him figure out how accomplish his greatest goal without turning it into an unhealthy obsession.

By 1989, when Hawk was 20, he tried the 900 but it went horribly wrong. He landed on his back and broke a rib. Hawk continued to practice, but he got frustrated and injured.

Hawk says he learned every aspect of the trick, sunk his whole mind, body, and soul into trying to do it, but he couldn't land it.

"At some point, I quit trying," says Hawk. "I felt like I gave it my absolute best effort."

Five years later, Hawk learned how to commit to the trick and figured out the spin. From 1995 to 1999, Hawk tried to master the landing. A handful of other skaters were trying to hit the 900 at the same time. Hawk and the others realized someone would hit it soon.

"I knew it was possible, but I couldn't figure out that last element," says Hawk.

During the X Games competition in 1999, Hawk says he put it all together.

"I realized I was falling forward each time and the key I was missing was that I needed to shift my weight mid-spin to my back foot," says Hawk. "When I started doing that, it all clicked."

Once in the halfpipe, the crowd asked for Hawk to do the 900. After a few attempts, he says, all these elements came together.

"The ramp was really good, the crowd was behind me," says Hawk. "I realized at that moment, I was either going to make it or be taken away in an ambulance."

On his eleventh attempt, Hawk stuck the landing. The crowd went wild. Hawk says that was the "biggest moment of his competitive career." As the crowd screamed, he felt that he had accomplished his dream.

Looking back, Hawk says he was focused on the 900, but it wasn't an obsession.

"The reason I chased the 900 for so long was for the sake of progression," says Hawk. "The thing I have always loved about skating is how it continues to evolve. It's a continually progressing art form and the 900 is one more milestone in the process."