So says the building's website, and it's right. Just a few hours ago, phillyskyline.com broke news of a supertall skyscraper proposal for the property bounded by 18th, 19th, Arch, and Cuthbert Streets (currently a surface parking lot). At 1500 feet, the American Commerce Center would dwarf Philly's recently-crowned king, the Comcast Center (975 ft), and if completed today, would stand as the tallest building in the Western Hemisphere and fourth-tallest building in the world. All......