Portion of one of the tubes of the Britannia Bridge, 1850.

UNITED KINGDOM - JUNE 30: Engraving by Day & Son after a drawing by Matthew Forster, showing an isometric projection of a portion of one of the tubes of the Britannia Tubular Bridge. The bridge was designed by Robert Stephenson (1803-1859) and was completed in 1850. It was constructed to provide trains of the Chester and Holyhead Railway with a passageway across the Menai Straits from mainland Wales to Anglesey. The railway terminated at Holyhead, which became a major port for travellers to Ireland. From �The Britannia and Conway tubular bridges� by Edwin Clark (1814-1894), published in London in 1850. (Photo by SSPL/Getty Images)