I am very impressed by how many of these nations can be formed not by changing the people who inhabit them, but by changing what they call themselves. In the Americas, Africa, and Oceania especially, we often mistakenly assume that placenames were somehow inherent to the land, when in fact so many of them were just the names of explorers (America), geography (Indonesia), or the color of the trees (Brazil). Even "Denmark" could have that name with 1066 still happening, if the Normans just find the Danes rather than the Angles in cultural dominance at the time.