Sulphite Railroad Covered Bridge

The Sulphite Railroad Bridge, known locally as the "Upside-Down Covered Bridge," carried the Boston and Maine Railroad across the Winnipesaukee River between Franklin and Tilton. Built around 1896, it is believed to be the only surviving upside-down covered railroad bridge in the United States: the rail bed sits on top of the structure, and the covering shelters the Pratt trusses below rather than the trains above. It is about 234 feet long across three spans on granite piers, with a central span of roughly 180 feet. It takes its name from the sulfite hauled to Franklin's paper mills.

Out of service since 1973 and damaged by a 1980 arson fire that burned off its siding, the bridge survives as a striking ruin and remains listed on the National Register of Historic Places (1975).