|Low angle view at the Flatiron building and street clock in New York City . The Flatiron Building, or Fuller Building is one of the landmarks of New York City. It is located at 175 Fifth Avenue in the borough of Manhattan, and is considered to be one of the first skyscrapers ever built. Upon completion in 1902 it was one of the tallest buildings in New York City. The building sits on a triangular island block at 23rd Street, Fifth Avenue, and Broadway, anchoring the south (downtown) end of Madison Square. The neighborhood around the building is called the Flatiron District after its signature building.