In Portland, they built the city on very mucky swampy tidelands, so they elevated the city on top of a level of tunnels called the Shanghai Tunnels, just to stabilize the foundation a bit more. The tunnels had trap doors in various pubs where bartenders would get random men who patronized their establishment drunk to the point of being defenseless or even passed out. Then they would dump them through the trap doors down into the tunnels, where they would remove their shoes so they couldn't run away, and toss them into a dark cell. Once they had enough men in cells, they would be taken to a waiting ship to be forcefully enlisted as part of the ship's crew and forced to work on the ship for a while. The whole abduction was called, appropriately, being Shanghaied. Hence the name of the tunnel network.

I don't live in the city, but they do sometimes do tours down in the Shanghai Tunnels, where you can still see the wheel barrows full of the unfortunate men's shoes, and the cells and all that. If you like creepy ghost story type tours, this might be worth a look.