The earliest roots of the modern study of topology (and [[graph theory]] in particular) lie in [[Leonhard Euler]]'s investigations of a famous puzzle from the 1730s. The town of Konigsberg (now [[Kaliningrad]]) was bisected by a river, which contained two large islands. There were seven bridges connecting the islands, as indicated in the accompanying image. The problem asked for a walk through the town which would cross each bridge exactly once: every bridge must be crossed once, and none more than once.
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The earliest roots of the modern study of topology (and [[graph theory]]) lie in [[Leonhard Euler]]'s investigations of a famous puzzle from the 1730s. The town of Konigsberg (now [[Kaliningrad]]) was bisected by a river, which contained two large islands. There were seven bridges connecting the islands, as indicated in the accompanying image. The problem asked for a walk through the town which would cross each bridge exactly once: every bridge must be crossed once, and none more than once.
[[Image:Konigsberg.jpg|center|alt=Layout of Konigsberg|Layout of Euler's Konigsberg]]
[[Image:Konigsberg.jpg|center|alt=Layout of Konigsberg|Layout of Euler's Konigsberg]]