The greatest surfer: Kelly Slater

Kelly Slater surfs at the Hurley Pro on Saturday, September 12, in Lower Trestles, California.

The greatest surfer: Kelly Slater

Slater rides a wave on August 18, 2014, during the 14th edition of the Billabong Pro Tahiti surf event in Teahupoo, Tahiti.

The greatest surfer: Kelly Slater

The 11-time world champion still competes at the highest level, often taking on surfers who weren't even born when Slater won his first title. At 41, he was a quarter finalist in the Billabong Rio Pro in Brazil on May 18, 2013.

The greatest surfer: Kelly Slater

Slater surfs during the first day of ASP world tour Billabong Rio Pro 2013 at Barra de Tijuca beach in Rio de Janeiro, Brazil, on May 09, 2013.

The greatest surfer: Kelly Slater

Having enjoyed a pro career in which he became surfing's most celebrated figure, Slater is now defying age barriers at the top end. He became the sport's the oldest champion after claiming the title in 2011 at age 39.

The greatest surfer: Kelly Slater

Slater rides a wave into shore during an aerial expression session at Bondi Beach in Sydney, Australia, on March 12, 2010.

The greatest surfer: Kelly Slater

In a rare interview, he told CNN about his "lifelong" commitment to furthering his ability: "I want to surf better tomorrow. I want to surf better in 10 years. When I'm 50, I want to be a better surfer than I am now."

The greatest surfer: Kelly Slater

As a child growing up on the waves at Florida's Cocoa Beach, Slater never imagined surfing would be a career. By 1992, he had become the youngest world champion at 20.

The greatest surfer: Kelly Slater

Slater is also a golf enthusiast. He is pictured at the 3M Celebrity Challenge in Pebble Beach, California, in February 2011.

The greatest surfer: Kelly Slater

Slater has lost friends to drowning and still faces the dangers of surfing every day. But he is defiant: "It makes you think about what it's worth. But what's life worth? Life's worth experiences and it's worth the people in your life too," he said.

The greatest surfer: Kelly Slater

For Slater, surfing is more than just a sport: "Surfing is my religion, if I have one."