I visited Kaliningrad in 2007 and puzzled my hosts by asking them if I could see the famous bridges. They hadn't heard of Euler and the Bridges of Königsberg. I was astonished.
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.
> 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.
From Google Maps it seem like it currently is possible to walk all the bridges, although you can't end where you started. Two of the original bridges have gone, two more have been built (not in the same locations as the destroyed ones), and there are two additional bridges that are within the city limits now but wouldn't have been in Euler's time.
I grew up in Kaliningrad. I haven't heard about this puzzle until I moved to US. I think this is partly because graph theory or topology are considered too advanced to be studied in typical schools and partly because very few residents know much about Konigsberg history. It's kinda like very few Americans know much about American Indian history before Columbus.
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.