Hopi Antelope Priests chanting during a Kisi Moki snake dance. Photochrom by the Detroit Photographic Co., with (if you can read the barely visible text on the image) a copyright date of 1902 - meaning the original has long passed into the public domain.
I did a restoration of it, which was fairly thorough, but there's only so much you can do with a relatively small image. Total time: About 1-2 hours, but, eh, I know someone this'll make very happy