The geography and history of Lyon are defined by two rivers. Hemmed in to the west by the rocky outcrop that is Fourvière hill, the city's growth over the centuries has depended on its inhabitants' ability to cross, bridge and eventually settle on the opposite, eastern banks of first the Saone and then, much later, the far larger Rhone.
But whereas the course of the Saone was comparatively easy to control, the mighty Rhone was prone to flash flooding, and numerous attempts to rein it in were literally washed away. So it wasn't until the late 19th century that someone came up with a plan that worked.
The outcome was nothing short of revolutionary - for both Lyon and France as a whole.
The outcome was nothing short of revolutionary - for both Lyon and France as a whole.