One of William Henry Jackson's "mammoth plate" exposures, made using 18x22 inch glass negatives, a massive view camera, assorted assistants, pack animals and a mobile darkroom that he hauled around by rail with chartered locomotives. This image comes from a number of 8x10 copy negatives exposed in the 1890s from the original 18x22 mammoth plates, which evidently are too big or fragile to scan.

1891. "Mexican Central Railway -- bridge over the Santa Rosa River." 8x10 glass plate made from an 18x22 negative by William Henry Jackson. View full size.