I found an atlas from 1943 in a used book sale. It not only had country's maps and population figures, but also maps of notable cities.
The map of Manhattan would not have changed considerably between 1940 and today. The biggest changes between then and now would be the addition of freeways, none of which actually get on to the island of manhattan (so far as I know, I may be wrong, having never lived there). Aside from a few extra bridges and tunnels, the street plan of manhattan was laid out in the mid 19th century, and remains largely unchanged...oh wait, I forgot the large reclaimation projects. Battery park and the World Trade Center area were once water, which has since been filled in. They would not have existed in the 1940s And the use of much land has changed. What were vast dockyards in 1940 are now vast parklands. This probably wouldn't show up on a map. "The Waterfront" used not to be a very nice place. Now it is. I expect that the character of many regions are vastly changed. You won't find that on a map.