Flat Iron Building at Broadway and Fifth. ca. 1913, New York, New York, USA, FLAT IRON BUILDING, BROADWAY AND FIFTH AVENUE, NEW YORK CITY. Fuller Building, generally known as the Flat Iron building stands at the intersection of Broadway and Fifth Avenue facing 23rd Street. Was the first steel frame sky scraper built in the world. it is 300 feet high and contains 120,000 square feet of floor space above ground and 13,340 square feet under the sidewalk.