Lord Rogers’s Tower 3 at 175 Greenwich Street, between Dey and Cortlandt Streets, is a flat-topped building with asymmetrical shoulders and the diagonal beams of the exoskeletal framework seem to echo the rooftop of Tower 2. The building will rise 1,155 feet, reaching the higher pinnacle at the antennas. It will have five trading floors, three retail floors, nine mechanical floors and 54 floors of offices, for a total of 71 stories.