14 January 2015
Last updated at 21:01
Two climbers trying to scale the sheer face of El Capitan in Yosemite National Park are inching towards the top of the 3,000ft (914m) peak.
Kevin Jorgeson, 30, and Tommy Caldwell, 36, are expected to reach the summit on Wednesday.
They are attempting to be the first climbers to do so without aids, except for harnesses and ropes to prevent deadly falls.
They began the half-mile ascent on 27 December 2014.
Spokeswoman Jess Clayton said the men will not give interviews at the top but will discuss the climb on Thursday.
Eric Jorgeson, Kevin Jorgeson’s father, told local media his son has always been a climber and watching him fulfil a long-time dream makes him proud.
“He climbed everything he could think of. It made us nervous early on as parents, but we got used to it,” he said.
He and his son had begun climbing the other routes to El Capitan’s peak in California when Kevin was 15, making it a birthday tradition each year.
At the scene
Alastair Leithead, BBC News, at the foot of El Capitan
With the naked eye it’s a strain to make out the two small figures climbing high up the smooth, sheer face of El Capitan.
But with a long lens you not only see them, but can even sense the effort and concentration required to get through what they hope will be their 19th and final day of climbing.
The razor sharp granite of the infamous Dawn Wall almost beat Kevin Jorgeson as he repeatedly tried and failed to conquer the hardest section.
With his fingers cut to ribbons he had to wait days for them to heal before he tried again – and finally succeeded. Now reunited with his partner Tommy Caldwell, the two men are close to making history and free-climbing one of the most difficult routes in the world.
A crowd has gathered at the foot and at the top to await their arrival. The weather is cold, clear and sunny and having survived the hardest sections the men only have to keep their nerve and their concentration to complete what many thought was an impossible climb.
“I feel like the most proud person in the world right now,” Mr Caldwell’s sister, Sandy Van Nieuwenhuyzen, said.
“I’m just going to hug. Just hug. No words necessary.”
During the climb, both have taken rest days to wait for their skin to heal, using tape and superglue to speed the process.
How do they do it?
Kevin Jorgeson grips the surface
- The rock face is not totally smooth, it has some cracks, lumps, rough edges and other irregularities
- The climbers wear high-friction shoes and climb at night in cooler weather
- When necessary, they rest fingertips and use treatments to heal broken skin
How do you climb a smooth rock face?