The awe-inspiring Ribblehead Viaduct.

This viaduct was opened in 1875 for the famous Settle to Carlisle Railway.
It is 440 yards (400 m) long, and 104 feet (32 m) above the valley floor at its highest point. It is made up of twenty-four arches of 45 feet (14 m) span, with foundations 25 feet (7.6 m) deep. Every 6th pier is 50% thicker to mitigate against complete collapse should any pier fail. The north end of the viaduct is 13 feet (4.0 m) higher in elevation than the south end leading to a gradient of 1:100. 1.5 million bricks were used in the construction and some of the limestone blocks weighed 8 tons each