E_R, I believe once or twice you said that underground tunnels was something that fascinated you, and I know we've come across those on NLA before. I saw this:
Underground Tunnels of Los Angeles – Los Angeles, California - Atlas Obscura
Discover Underground Tunnels of Los Angeles in Los Angeles, California: During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.
I haven't looked at this further, but I thought I'd post the link here in case I don't get back to it or whatever.
https://www.atlasobscura.com/places/...ls-los-angeles