The Seven Bridges of Konigsberg

Konigsberg Map | Konigsberg Bridges | Konigsberg Bridges Alone | Konigsberg Graph | Konigsberg Graph Alone

The city of Königsberg in Prussia was around the Pregel River, and included two islands which were connected to each other and the mainland by seven bridges.

The problem was to find a walk through the city that would cross each bridge once and only once, with the following rules:

• the islands could not be reached by any route other than the bridges,
• every bridge must have been crossed completely every time, and
• the walk need not start and end at the same spot.

Leonard Euler was able to answer this question in 1735 and from the method of his answer began the mathematical field of graph theory.