One of my hobbies is old maps, and I wanted to share a fun one with the group! The next time I need an "Arkham and environs" or "weird New England" map, I think I'm going to use this one (public domain thanks to the Library of Congress). The cartography is gorgeous, the place names are so evocative, and the geological cross-section at the bottom is chef's kiss!
The story behind this map, it depicts a proposed rail line that was never built. A competing company did bring rail travel to the area a few years later, but it took a more coastal route, to East Boston (present day site of Logan airport). So while this is a "real world" map, it's of something imaginary, that never existed.
https://www.loc.gov/resource/g3761p.rr002320/