In 1861, the photographer Carleton E. Watkins hauled hundreds of pounds of camera equipment, sheets of glass and chemicals into Yosemite Valley in a darkroom wagon. For the first time, Mr. Watkins captured photographic images of these granite cliffs and waterfalls.
After seeing Mr. Watkins’s photographs, President Abraham Lincoln signed legislation in 1864 preserving the valley for the public and leading the way toward what would become the National Park Service.
In a strange coincidence, the molten effect of the sun on Horsetail Fall resembles another famous and highly photographed firefall here, one involving actual fire. Beginning around 1900, park workers collected Red Fir bark and built a large bonfire atop Glacier Point. After dark they pushed the red embers off the cliff in a cascade of glowing red coals, a must-see spectacle for the summer tourist set.
But in 1968, park officials ended the Yosemite Firefall, citing its man-made unnaturalness (the park banned feeding bears for the same reason). Five years later, the photographer and mountain climber Galen Rowell was driving through the park after a winter climb when he spotted the light catching in Horsetail Fall. He rushed across the valley and took what is believed to be the first image of the illuminated waterfall.
Mr. Rowell died in a plane crash in 2002, but his “Last Light on Horsetail Fall” remains the most well-known photograph of the apparition.