United States Steel Corporation’s world headquarters is located in the U.S. Steel Tower, which is situated along Grant St. in downtown Pittsburgh, Pa., and showcases the company’s COR-TEN® steel. When its construction was completed in 1971, the building was considered to be an engineering masterpiece and was featured in many architectural and engineering magazines. The 62-story tower, once the tallest building between New York and Chicago at 841 feet and 64 stories, is the tallest building in downtown Pittsburgh, which is situated at the confluence of the Monongahela, Allegheny and Ohio rivers. (United States Steel Corporation)