This video, shot on August 29, shows a group of climbers installing 39 solar-powered LED lanterns temporarily up the Snake Dike route on Yosemite's Half Dome. It was an art piece titled Half Dome Bolted Light, directed by climber Megan Sullivan, in celebration of the American Safe Climbing Association (ASCA).
The organization has replaced and re-bolted over 14,000 climbing bolts on popular climbs across the country over the last 18 years. As they explain, they "return classic climbing routes to their original danger level by replacing deteriorating old fixed anchors, usually bolts, with modern camouflaged gear." But, they add, despite the organization name, "We do not add bolts to make climbs 'safer.' Climbing is inherently extremely dangerous."
As part of the artwork, the red lights were placed on all of the bolts and anchors up the route, while the white lights illuminated the rest of the route. All of this only lasted five hours, and all the lights were removed as the group rappelled down afterwards.