Identifying the Age of a Map

Don’t you just hate it when you stumble upon a map, but you cannot place the time period of the geographies? Well if you haven’t, who cares, because xkcd has a great flowchart to help you anyway.

Sum the number of Yemens and Germanys…
Sum the number of Yemens and Germanys…

Credit for the piece goes to Randall Munroe.