But out of them all, the abandoned Cincinnati Subway System - built in the 1920s - is the most interesting. Though originally planned as a 16 mile project, only seven miles were tunneled. Six stations were built, and no tracks were laid. Three stations remain, and the other three were demolished, with barely visible entry points into the tunnel.
According to historians, the city couldn't secure the necessary funding to complete it during the 30s or World War II. Unfortunately, the tunnel fell into disrepair, and the region was looking into other ways to accommodate residents. Cincinnati Transit has the entire history of this nearly forgotten structure. The four subway pictures below are courtesy of Cincinnati Transit's truly informative website.
A 1920s picture of the early construction phase, left, and a layout