A fantastic photo that shows a huge map being installed through a window at the Northern Pacific offices in St. Paul, Minnesota. The short article that accompanied the photo when it was first published in Popular Mechanics in February 1917 says:

A railway map of enormous size was recently installed in the immigration department of the Northern Pacific Railway offices in St. Paul. It measures 69 ft. long and 11 ft. wide and required the services of nearly a dozen men to carry it. The map shows that portion of the United States between the eastern boundary of Minnesota and the Pacific coast, and the entire Northern Pacific Railway system, including practically every station on the line. The whole representation is done on such a large scale that even the lettering used in the names of the smallest towns can easily be read several feet away.

Despite its great size, the map appears to be pretty coarsely executed. The presence of what looks like large handwriting – it’s not sign writing, but is written in a natural hand – across the top of the map leads me to think that this is some kind of photographic enlargement from a much smaller original map, although I have no idea how such large prints would be accomplished with early 20th century technology.

Source: Making Maps: DIY Cartography