Barrage de la Rance Brittany

Built in 1966, this 750m bridge over the Rance estuary carries the D168 between St-Malo and Dinard, lopping a good 30km off the journey. A feat of hydroelectrics, the Usine Marémotrice de la Rance (below the bridge) generates electricity by harnessing the lower estuary's extraordinarily high tidal range – a difference of 13.5m between high and low tide. There is a drawbridge, while the tidal power station was the world's first when constructed and, until 2011, the largest on the planet.