OpenHistoricalMap
Being Dutch and a history-buff, I have one mayor gripe with historical maps, that sees land as 'moving lines' on a fixed map. When I look at a historical maps (also in books), I often see the Netherlands represented in it's current form, i.e. containing land that is not even 50 years old, being prestent hundreds or even thousands of years. I get that it is an intricate history, and maybe too much effort in some cases, but please at least remove flevoland. https://en.wikipedia.org/wiki/Flevoland