Leonhard Euler

If you are ever in Kaliningrad, Russia (you have no reason to go to Kaliningrad, but indulge us), you might be inclined to traverse a very famous mathematical problem: the Seven Bridges of Konigsberg (Konigsberg being Kaliningrad's name under the Prussian rule).

A river ran through Konigsberg that separated it into two parts. There were two islands on the river, and seven bridges connected various land masses. Was it possible to make a path that traverses all the bridges just once each? Many spent years trying to crack the puzzle.

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