This is the city's buzzing financial heart, home to Wall Street and glittering skyscrapers. Sidewalks bustle during the week and, after work, young professionals fill the restaurants and bars of the South Street Seaport and pedestrian-only Stone Street. The sombre National September 11 Memorial and Museum, in the footprint of the Twin Towers, is also here. Above it all is the observatory atop One World Trade Center.