The Iron Bridge

Cast-iron arch, 1779. Proposed by the Shrewsbury architect Thomas Farnolls Pritchard and built under Abraham Darby III over the River Severn in Shropshire. This is where the iron bridge begins, and the charm is that its builders had no rulebook. Its 30-meter single span uses 378 tons of iron, and the parts are fastened with dovetails and other carpentry joints, as if the ironworkers were still thinking in timber. Look at the five semicircular ribs from the riverbank and you are seeing a new material borrowing an old craft's logic. The gorge setting, wooded and quiet now, makes it easy to forget this was once the furnace of industrial Britain.