1750-1791

English inventor who built the world's first cast-iron bridge. Darby's bridge, which crossed the Severn River in Coalbrookdale in England, was a major improvement over the wooden or masonry bridges that preceded it. Unlike wood, iron would not rot (although it would rust if not properly maintained). Unlike masonry, the relatively high strength and low weight of cast iron allowed spanning larger rivers safely, without impeding navigation in the process. This made possible increasingly long bridges, culminating in such classics as the Golden Gate and Erasmus Bridges, among others.