Tunkhannock Viaduct

The Tunkhannock Viaduct in Nicholson, Pennsylvania, was the world’s largest concrete structure when it opened in 1915. It is 2,375 feet long and rises 240 feet above the surrounding area. The bridge has been in continuous use for well over a century.

Image: “Freight Train on the Tunkhannock Viaduct. Nicholson, Pennsylvania (273-8)” by David Plowden (1973). From Yale University, Beinecke Rare Book and Manuscript Library