�The Menai Suspension and Britannia Tubular Bridges�, Wales, c 1855.

UNITED KINGDOM - JUNE 04: Coloured lithograph by Thomas Picken showing the two bridges built across the Menai Straits in the 19th century. The nearer of the two bridges, the Menai Straits road bridge was designed by Thomas Telford (1757-1834) and was built between 1818 and 1826. The bridge deck was damaged by a gale in 1839 and the deck was replaced in 1893 with a steel one. The Britannia Tubular Bridge was designed by Robert Stephenson (1803-1859) and was completed in 1850. It was constructed to carry trains across the Menai Straits from mainland Wales to Anglesey. Stephenson�s solution to the problem of how to carry the weight of trains pulling multiple carriages across the straits was to construct the bridge from rectangular iron tubes, through which the trains would run. (Photo by SSPL/Getty Images)