The Königsberg bridges problem

Behold the turtle only makes progress when he sticks his neck out.

James Bryant Conant


The Königsberg bridges problem originates in the city of Königsberg, Prussia (now Kaliningrad, Russia). This city was built on the banks and islands of the Pregel (Pregolya) River.

The map shows how the seven bridges are situated on an upper bank, lower bank, Island 1, & Island 2.


As the residents of Königsberg travel around their city, a curious question is poised:

Is it possible to take a route that crosses each bridge only once? And if so, how?


Konigsberg Bridges map















1735 Leonhard Euler, of Switzerland, uses graph theory to determine a solution of the Königsberg bridge problem.


Try a guess and check strategy with diagrams to show how using different variations of bridge use traps you without another bridge to cross.



Dr. Robert Sweetland's notes
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