Local aesthetics are an important consideration, but it was clear from the start that the real X factor in the Minneapolis project was the snow. From 1982 to 2013, the Vikings played in the Metrodome, which relied on an air-supported fiberglass fabric roof to keep out the cold. Almost from the moment the ceiling was raised, it was falling. The material tore and leaked; in 1981 (yes, that's before it even opened), 1982, 1983, 1986, and 2010, it deflated like a busted balloon, dragged to the turf by the weight of recent snowfall. The new U.S. Bank Stadium was constructed on the same site and even uses some of the same hull at its base. But everything else had to be brand new and improved—especially the roof.