The river Pregel ran through the town of Konigsberg. In the river were two islands, connected to each other and the rest of the city by seven bridges.
The residents of Konigsberg challenged each other to walk through the city, and cross each of the seven bridges exactly once.
Can you find a path that they might have taken?
This is the 'Seven Bridges of Konigsberg' puzzle – tackled by Leonhard Euler in 1736.