The Iron Bridge

The simply named Iron Bridge in Shropshire, England is the first arched bridge in the world to be made of iron yet is designed as though it was made of wood.

Opened in 1781 to bridge the River Severn, the span took advantage of a newly installed iron forge to create the over 300 tons of iron parts. Since iron was expensive and hard to work with in the 1700's a construct so large as a bridge had never been made, so when the designers laid out the design, they based it on wooden bridges with a series of individual struts that interlocked. Some of the pieces were in fact so large that they had to be cast in large custom-shaped holes in the ground. Due to the bridge's historic significance, vehicular traffic is no longer allowed, and the site is now a foot bridge only.