Larger in scale and more detailed. If Larger and more challenging is what you’re after ICONX is perfect for you! Make a BIG impression with our premium line of DIY metal models. From steel sheets to 3D models this ICONX collection offers a larger size with enhanced detail. Willis Tower is a 108story 1 451foot (442 m) skyscraper in Chicago Illinois. At the time of its completion in 1973 it was the tallest building in the world surpassing the World Trade Center towers in New York and it held this rank for nearly 25 years.