William Henry Jackson's photos of his visit to Chaco Canyon were lost as a result of a failed new photographic process he utilized while at Chaco.
"Sketch of Jackson's Stairway, located on the north wall of the canyon near Chetro Ketl. William Henry Jackson, a photographer for the US Geological and Geographic Survey of the Territories, was the first to describe the prehistoric stairway carved into the sandstone cliff face.
May 10, 1877
By William H. Jackson
Chaco Culture National Historical Park"