Independent Subway System map in 1940
<a href="https://it.wikipedia.org/wiki/Utente:L9A8M" class="extiw" title="it:Utente:L9A8M">L9A8M</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>, Background map from Openstreetmap (<a rel="nofollow" class="external text" href="https://www.openstreetmap.org/#map=0/-90/-130">http://www.openstreetmap.org</a>)