The construction site of the century... This series of images propels us into an atmosphere of unique and ephemeral moments that will leave behind a living testimony to man's achievements.400 workers, almost ten years of construction underground and at great altitude, 17 km of tunnels dug, 1.7 million m³ of rock excavated: the Nant de Drance construction site is one of superlatives. It will give birth to one of the most powerful pumped storage power plants in Europe. With its 900 MW, it will produce approximately 2.5 billion kWh per year. It will be commissioned progressively from 2019.