The geometry of the Stadium is made clear in the rigorous reinforced concrete structure of the two central stands. The body of the steps is cut by three circular section tunnels allowing people to cross. The roofing of the stands has been constructed by using two laminar slabs of reinforced concrete, with a 25 cm thickness, suspended simply by a cable system arranged transversally across the pitch. The 220 metres of roofing span is a unique example in the world, from a structural point of view. The executive project has been developed with extensive experimental research in wind tunnels.