I'm wondering what the amazing mapping advance will be 20 years from now. Real time street views of all metropolitan areas?
We drove around and saw a couple of what I think were the bridges dating from Euler's time. Others had been destroyed in WW2 and/or replaced with modern, larger bridges.
I read a while ago that the destruction had actually rendered the bridges problem soluble (that is, that there is a modern Eulerian path); but I don't know if that was true at the time, or is still true.
You'd be unpleasantly surprised if you saw a turn-of-the century-math high school textbook (1900 or so.) Pretty advanced stuff towards the end.
Well, calculus had been invented before Euler was born, and a lot of advanced math had been developed by the time Gauss appeared (a lot of it by none other than Euler).