The dull gray/black 841 foot 64 story tall triangular, corner indented mass of steel known as the U. S. Steel Tower or USX Tower was completed in 1970. The building is unique in many ways , for one thing it does not need to be further weather proofed or cleaned because of its finish. It has been chemically treated so that it will not decay or rust and therefore does not need to be scraped, polished, buffed, waxed, or refaced, as other buildings do. It was the tallest building outside New York and Chicago for years. It is currently the tallest building in Pittsburgh.