How do Shanghai tunnels work? — Erica, Portland, Ore.
In Portland, Oregon there is a section of the old Chinatown area where a number of bars and restaurants are connected by underground tunnels. These tunnels are known as the “Shanghai tunnels” or the “Portland underground”.
There are two stories around these tunnels. One indicates that the tunnels were use to move supplies from the nearby docks to the businesses without having to deal with people and traffic on the street. This is the same kind of system used under Disney World (and many other large theme parks) today.
The second story indicates that the tunnels were used to kidnap patrons of the bars and send them away to be slaves. A patron would be drugged, dropped into the tunnel system through a trap door, and then carried to a waiting ship. According to this article, there is not a lot of evidence that this practice actually occurred using the tunnels in Portland, although Shanghaiing did occur along the west coast, especially in San Francisco during the 1800s.
This amateur video shows one of the tunnels in Portland: