Data source: https://www.openstreetmap.org/
Author: https://old.reddit.com/r/MapPorn/comments/1f38xe2/tennis_court_density_of_europe/
Population map of Europe
Oh, another population density map.
Is it, though? Is Spain, Poland and Balkan so much less populated than Germany or France?
Yes.
Are we looking at the same pictures? Spain is less dense, but Poland seems mostly denser than rural France and Balkan roughly the same.
Go see in person or find better data. Spain is a desert between big towns. Poland has only 35ish M people on all that land. You can drive for hours in west Balkans without seeing a single settlement. Croatia, for example has less than 4M people in an area which is bigger than the Netherlands. The Netherlands has like 18M people.