The bridges of Königsberg is a mathematics problem solved by Leonhard Euler that concerns whether there is a path through the city of Königsberg that traverses each one of its bridges exactly once. Although the problem was a very simple one to state, Euler's solution had a seminal effect on mathematics, introducing ideas that were to lead to the development of two new branches of mathematics: graph theory, which deals with questions about networks of points that are connected by lines, and topology, which is the study of those aspects of the shape of an object that don't depend on length measurements.

Königsberg, which in Euler's time was located in Prussia and is now part of Germany, is a town that is divided into several different parts by the Pregel River. There are two...