Located south of Nora Springs, this extremely unique stone arch bridge crosses Hawkeye Avenue.
Built in 1889 to replace an older wooden trestle, this bridge features a single stone arch main span. However, built into the parapet like abutments are stone box culverts, originally intended to be pedestrian underpasses.
Judging by the grand scale of this bridge, it is likely that this route was the main road into Nora Springs at one time. In addition, an abandoned highway truss still stands north of this bridge.
While most railroads had switched to standard stone arches for cases like this, the Burlington, Cedar Rapids & Northern continued to use stone arches custom designed to every situation. As a result, some very unique arches were built.
This one however takes the cake for uniqueness. The pedestrian tunnels are an interesting feature, as they would more commonly be seen in places further east, not a town in Iowa with a low population.
Overall, the arch remains in excellent condition. It is reportedly haunted, and is a tourist attraction of sorts. As of April 2021, gates have been installed across Hawkeye Avenue to the south, although the bridge is still accessible by walking. However, it appears the bridge has some structural issues. Small spots of corrosion have eaten away at some bracing inside the girders. Unchecked, this could become a problem.

Historic photo of the bridge. Credit to PhotoLibrarian on Flickr, used with Creative Commons permission.
The author has ranked this bridge as being regionally significant, due to the incredibly unique design.
The photo above is an overview.