Millau Viaduct mid-1998. After undergoing wind tunnel tests, the shape of the road deck was altered, and detailed corrections were made to the design of the pylons. When the details were eventually finalised, the whole design was approved in late 1998. Once the Ministry of Public Works had taken the decision to offer the construction and operation of the viaduct as a grant of contract, an international call for tenders was issued in 1999. Five consortia tendered: Piers were built with Lafarge high performance cement. The pylons of the Millau Viaduct, which are the tallest elements (the tallest pylon – ) were
Millau Viaduct World Wildlife Fund (WWF), "France Nature Environnement", the national federation of motorway users, and Environmental Action. Opponents advanced several arguments: Two weeks after the laying of the first stone on December 14, 2001, the workers started digging the deep shafts. There were four shafts per pylon; deep and in diameter, assuring the stability of the pylons. At the bottom of each pylon, a tread of in thickness was installed to reinforce the effect of the deep shafts. The of concrete necessary for the treads was poured at the same time. In March 2002, the pylons emerged from the ground. The