1779 The world's first iron bridge

The Ironbridge Gorge is a deep gorge formed by the River Severn in Shropshire, England. Originally called the Severn Gorge, the gorge now takes its name from its famous Iron Bridge, the first iron bridge of its kind in the world, and a monument to the industry that began there. The bridge was built to link the industrial town of Broseley with the smaller mining town of Madeley and the growing industrial centre of Coalbrookdale. It was formed during the last ice age when the output from the previously north flowing river became trapped in a lake (Lake Lapworth) created when the Irish Sea ice sheet dammed the river. The level of the lake rose until it was able to flow over the hills to the south. This flow eroded a path through the hills forming the gorge and permanently diverting the Severn southwards.