Metropolitan France is shaped like a hexagon, and is often referred to as l’hexagone. You can connect the points of the hexagon to make nine diagonals.
A few years ago I found out that French Audax cyclists have for decades made these diagonales into cycling challenges. You have to cycle a diagonal within a given time-limit, collecting official stamps on the way, have them homologués officially and write an account of your ride to be able to call yourself a diagonaliste.
Les Diagonales de France (in French)
It seemed to me that cycling each of these a bit more slowly, with no time-limit, no stamps and no homologisation, would be an enjoyable way to get to know France at ground level, so that’s what I’m doing.