It's 1840 and engineers have been using wood to build railroads. Inexpensive, but it required a lot of maintenance and often caught fire. Stone was far more durable, but expensive and required a lot of work. Enter reinforced concrete. When the Delaware, Lackawanna and Western Railroad or the DL & W had to reroute its main line in the early 1900s, the result was the Tunkhannock Viaduct, the largest reinforced concrete structure of its kind.
The Tunkhannock Viaduct, named for the creek it crosses, is also known as the Nicholson Bridge. It's nearly 2,400 feet long and rises 240 feet above ground. The Tunkhannock Viaduct did what it was meant to do: shorten the main rail line from Scranton to Binghamton, New York, improving speed and efficiency. But it is also a famous, highly photographed structure that a noted novelist once called one of the true wonders of the world.
