This titanic feat of engineering is worth the trip. The earth dam with a waterproof clay core was the first to be built on such a scale in France, applying a technique widely used in the USA. 14 million m3 of clay extracted from the bed of the River Durance were necessary to create the 600m-long slope, 123m high and 650m wide at the base. At the foot of the dam, the water and energy centre offers a closer look at the dam.