At the 91st Academy Awards ceremony in Los Angeles on Feb. 24, a curious thing happened. As dozens and dozens of actors and directors climbed the stairs to receive an Oscar, one of the people on stage accepting an award that night was not an actor or a director or anyone involved in filmmaking at all.

He was a rock climber.

Alex Honnold, a lanky and athletic 33-year-old California native, appeared on the Academy Award stage with the creators of the film “Free Solo,” which won the Academy Award that night for Best Documentary.

Why was Honnold on the stage?

“Free Solo” is a film about Honnold’s June 3, 2017, ascent of El Capitan at Yosemite National Park. El Capitan is a near-vertical 3,000 granite monolith in Yosemite’s sweeping valley. The various routes up the rock formation are some of the most prized achievements in climbing. And El Capitan and Yosemite in general are one of the most popular rock-climbing places in the world.

Honnold’s climb in June 2017 was done in “free solo” style. That is, Honnold climbed the entire 2,900-foot Freerider route on El Capitan’s vertical face without any ropes or protection. Honnold wore climbing shoes, a T-shirt and a pair of pants.

Other than a bag of chalk for sweaty hands, Honnold carried nothing else with him. He completed the climb in three hours and 56 minutes, and it quickly was called one of the greatest athletic feats of any kind, including a contributor to the New York Times.

Honnold appears neither crazy nor super human. A native of Sacramento, Calif., Honnold began climbing in a local gym at age 5. A competitive climber in his teens, Honnold did not consider himself especially gifted or strong.

He spent one year at the University of California, Berkeley, before dropping out to climb full time. Living out of his car, he climbed up and down the California mountains.

Free solo climbing is a style of rock climbing in which the climber does not use any harnesses, ropes or other gear to protect against falling.

Essentially, the climber will walk up to the rock face and just begin climbing, with only rock-climbing shoes and a bag of chalk. The climber will rely only on skill and experience to complete the climb. Above 50 feet is generally considered the “death zone,” meaning that any fall above that height likely would be fatal.

A free solo climb of El Capitan had been a possible target for many years by prominent climbers. The two climbers who acknowledged that they were actually planning to do the climb already died, however, in separate accidents. Michael Reardon drowned in 2007 off a sea cliff in Ireland, and Dean Potter died in a base-jumping wingsuit accident in Yosemite in 2015.

Why would a climber risk life to do free solo climbing?

Free solo climbers cite the simplicity and focus required of climbing without protection. It is just them and the rock and nature. Climbers also cite the speed that they can climb. Honnold’s climb of El Capitan took three hours and 56 minutes. Most climbers take a few days to climb El Capitan.

Honnold’s presence at the Academy Awards is one byproduct of the increasing popularity and attention being given to rock climbing.

Some people have considered free soloing too risky and are moving away from it. Clif Bar, the energy bar company, dropped its sponsorship of Honnold, as well as a few other free solo climbers, because it viewed the free solo style too risky and dangerous and was uncomfortable with it.

Climbing of all kinds has grown in popularity in the United States.

Outdoor climbing’s increased in popularity has forced the National Park Service to continually revise its rules and regulations to protect not only the climbers but the environment as well. Yosemite National Park, like other places, have seen such an increase in climber traffic that rules needed to be established for even basic things.

Working with climbers and outdoor enthusiasts, the National Park Service develops rules and regulations to protect the natural landscape and climbers and revises existing rules to improve them. Camping, litter, human waste, car parking and abandoned ropes and climbing gear all have been addressed by the National Park Service.

The goal is to minimize the impact on the natural landscape, which is to remain pristine in national parks. An individual climber may not make that much of an impact, but the volume of climbers seen in recent years has required stricter rules.

Climbing’s increase in popularity also will be reflected at the 2020 Summer Olympics in Tokyo. For the first time, sport climbing events will be held at those Summer Olympics.

Competitive sport climbing is different than normal outdoor rock climbing. Competitive climbing is done on an artificial climbing structure, such as a climbing wall. The sport has three disciplines: speed climbing, bouldering and lead climbing. In Tokyo, the Olympics will have two events, one each for men and women.

Sport climbing was identified in 2015 by the International Olympic Committee as a possible new sport for the 2020 Summer Olympic Games and was approved for the Games in 2016. In 2018, sport climbing was included in the 2018 Summer Youth Olympics.

The sport of climbing has grown widely in the last 20 years. While climbers such as Honnold continue to push the edge of what is possible, the rest of the world will be introduced in 2020 to the sport of climbing in Tokyo.