Until August 24, 1873, there had only been rumors about a natural cross of snow in the mountains of Colorado. Many claimed to have seen it and other were unable to find it. William Henry Jackson, an experienced wilderness photographer set out in August 1873 with the goal to prove its existence by taking a picture.
Previously, Jackson photographed during a wagon train to California in 1866 and was employed as an expedition photographer on Ferdinand Hayden’s survey of the Yellowstone region in 1871. His photographs became popular from Harper’s Weekly magazine.
After thousands of years of erosion, two deep ravines had formed in the steep rocky face of a mountain peak. Intersecting at a 90-degree angle, the ravines sheltered the winter snow from the sun well after the rest of the mountain snow had melted away. For a brief time, a nearly perfect cross of snow appeared on the rock face, though it often melted away later in the summer.
Jackson captured the cross that day and the best of the resulting photos became one of Jackson’s most popular and famous images, and it ended any further doubts about the existence of the Mount of the Holy Cross.
If you want to see more of William Henry Jackson’s photographs there are many on the internet. Here is one source from google images: