Forth Bridge, late 19th century.

UNITED KINGDOM - MARCH 03: Stereocard which when placed in a viewer, gave a 3-D image. Before the Firth of Forth railway bridge was completed in 1889, passengers were transported over the Firth of Forth by ferry. However, the building of the bridge meant that those people travelling north from Edinburgh got there much more quickly. The bridge was made from tubes of steel plate, that were 12' in diameter. It is the oldest railway cantilever bridge in the world. Designed by Sir John Fowler and Sir Benjamin Baker, it is still in use. (Photo by SSPL/Getty Images)