A world-renowned American free solo climber has died attempting to descend the side of a cliff face.
Brad Gobright, 31, fell around 300m (1,000ft) to his death in El Potrero Chico in northern Mexico.
His companion, fellow climber Aidan Jacobson, 26, fell a shorter distance and survived with injuries.
Gobright was best known for free soloing, or climbing without any safety gear, but at the time the two were abseiling, a technique using ropes.
Abseiling accidents are believed to be the most common cause of fatalities in the sport.
The two men were simul-rappelling - a technique where two climbers descend opposite strands of an anchored rope, with their bodies acting as counterweights to each other - with an 80m rope, the Outside website reports.
"We started rapping," Mr Jacobson told the Outside website, using the North American term for abseiling. "I was a bit above him. I was on the left. He was on the right. Then all of a sudden, I felt a pop, and we started dropping."
While Mr Jacobson crashed through a bush, which cushioned his fall, before striking a ledge, Gobright fell to his death.
"It was basically a blur," Mr Jacobson added. "He screamed. I screamed. I went through some vegetation, and then all I remember is seeing his blue Gramicci shirt bounce over the edge."
Born in California in 1988, Gobright first started climbing at the age of six.
He reportedly dropped out of an Orange County community college in 2009 and worked odd jobs to fund his climbs around North America, before his talent began to attract sponsorship deals.
"I always worked for four months, climbed for eight, and started over," he told Rock and Ice magazine for a 2017 profile.
Tributes to Gobright, who once held the coveted speed record on the Nose of El Capitan in Yosemite, have come in from across the climbing world.
Jim Reynolds, who set that speed record with Gobright, wrote on Instagram: "We will carry your spirit, dear friend."
"The climbing world lost a true light. Rest in peace," said Alex Honnold, focus of the Academy Award-winning documentary Free Solo.
"You will be dearly missed," Free Solo director Jimmy Chin wrote on social media, calling Gobright "a true climber's climber".
"He had a magic about him on the rock, unlike anyone I've ever met," wrote Alice Hafer, one of Gobright's climbing partners.
"He was so supportive and encouraging, always pushing me harder and believing in me."
It is unclear exactly what happened that caused Gobright to fall. But a Reddit climbing forum discussed the dangers of rappelling in the wake of Gobright's death, posting statistics which suggest more than a quarter of climbing accidents in North America happen during the descent.
"It feels like it's always rappelling... it's not over till you're on the ground folks," wrote one commenter.
Another said climbers can "let their guard down" after a long and tiring day, or become distracted in the rush to get down before the sun sets.
"It takes all of 20 seconds to check yourself, check your partner, and knot your ropes."