The first bridge in the world to use iron as the basic construction material was built in 1779 in Shropshire, England.

Built by Abraham Darby, it crosses the Severn at Coalbrookdale, with a span of about 100 feet and a height of 50 feet.

For more information about the bridge see:
Wonders of the World Databank
Secrets of the Past

Photo courtesy of the International Association of Bridge, Structural, Ornamental and Reinforcing Iron Workers.