Königsberg (Kaliningrad)

Königsberg, now known as Kaliningrad, was a historic city in East Prussia, famous for the "Seven Bridges of Königsberg" problem. This problem asked whether it was possible to walk through the city crossing each bridge exactly once without retracing steps. Mathematicians used this puzzle to develop graph theory, a branch of mathematics that studies relationships and connections. The city’s unique layout with rivers and bridges made it an ideal real-world example. Today, Kaliningrad is a Russian exclave on the Baltic Sea, retaining its historical significance and geographic distinctiveness.