The Millau Viaduct is a cable-stayed bridge that spans the valley of the River Tarn in southern France. It is the tallest bridge in the world, with one mast reaching a height of 343 meters—taller than the Eiffel Tower. Designed by engineer Michel Virlogeux and architect Norman Foster, the bridge was built to relieve traffic on the route from Paris to Spain. A unique engineering challenge was the 'launching' of the bridge deck; because the valley is so deep, the steel roadway was built on land at either end and then pushed out over the piers using high-capacity hydraulic jacks. The bridge is so high that it often sits above the clouds, creating a surreal sight for drivers that looks like a highway in the sky.