Article : Flyovers - Colegiul National C. Negruzzi (Iași - Roumanie)

One tries to connect a given number of towns by roads, with bridges (“flyovers”) to avoid crossings at intersections. What is the minimum number of bridges required for n towns? The problem is solved up to 6 towns, and for 7 and 8 towns examples are given that yield at least an upper bound of the minimum number of flyovers.