One of the most notoriously crappy pieces of infrastructure I can think of around here is the CPR underpass on Main Street in Winnipeg. It was built in 1904 to accommodate the CPR mainline and tracks leading to the CPR station. The station tracks are gone but the mainline trains still keep chugging through.
CPR owns the bridge structure and they claim it is still structurally sound, but it looks atrocious... it is basically a dank, crumbling tunnel in one of the dingiest parts of town. Whatever aesthetic merit it had was eliminated in the postwar years when the gentle curves were squared off to allow for greater height limits for traffic passing underneath.
If you are interested in seeing it there are some good pictures on a local blogger's flickr page:
https://www.flickr.com/photos/christ...th/2539960231/