Zoom out to the highest level on Google Maps, then zoom in to the level where the first city labels appear. Listed below are the 139 cities that appear at that level. How many can you name given the country and starting letter for each?
Occasionally there are anomalies, and a few of the 139 don't appear at the first zoom level with labels.
I've filled in a few of the "cities' that would have been almost impossible to guess.