The Brooklyn Bridge over the East River in New York is the first structure to use steel cable in a large-span suspension bridge, and it makes visible the material transition of 19th-century engineering — from iron to steel. The engineer John A. Roebling began the project; after his death his son Washington and Washington's wife Emily Roebling completed it.

The bridge carries two structural logics together. The two great supports founded in the riverbed are pointed-arch Neo-Gothic stone towers — heavy, traditional masonry working in compression. The four thick main cables that pass over these towers and are tensioned into anchorage blocks are light, modern steel working in tension. The deck is held in the air by vertical hangers descending from these cables. Roebling also added diagonal stays running from the cables down to the towers, giving the bridge extra rigidity — a hybrid system between pure suspension and truss.

What matters is the choice of material: until then suspension bridges used iron cable; Roebling preferred higher-strength steel wire, making possible the 486-metre main span — the longest of its time. The Brooklyn Bridge thus unites the weight of stone masonry with the lightness of steel tension in one structure and opens the age of the large-span steel suspension bridge.