We received a request to identify the source for the two cool maps below. I did a Google Image Search and found the source for one of them, but for the other one the map seems to have disappeared from the source. Anyone can help find the original? Thank you!
First image: source, according to Google: click here (but the image is missing)
Second image: source, according to Google: click here
Google also listed other similar images worth checking, see below:
This map of U.S. day vs. night city population appeared in Time magazine Nov. 26, 2007 issue.
Here is the original link to the published map