John Roebling moved his wire rope factory from Pittsburgh to Trenton in 1848, and the company went on to manufacture the cables for the Brooklyn Bridge, the George Washington Bridge, and dozens of other major suspension bridges. The sprawling complex of brick industrial buildings on South Broad Street and surrounding streets is a National Historic Landmark — the largest surviving 19th-century wire manufacturing complex in the United States.
The buildings are not fully open to the public, but the exteriors are worth seeing: massive multi-story red brick structures that give a real sense of the scale of Trenton's industrial past. Some spaces have been converted to studios and small businesses. The Roebling Machine Shop on Hamilton Avenue is the most accessible structure and the most photogenic.