Re-posting from earlier- seems that there are tunnels under Chinatown in many cities, going back to the 1800's. They were apparently built by Chinese immigrants, and used for smuggling, kidnapping, and other criminal activity.
cafemystery.blogspot.com/2010/02/san-francisco-chinatown-secret-tunnels.html
southsoundtalk.com/2017/04/25/stories-of-chinese-tunnels-in-tacoma-continue-to-this-day/
infamousnewyork.com/tag/chinatown-tunnels/
idahostatesman.com/news/article210321414.html
theculturetrip.com/north-america/usa/oregon/articles/a-brief-history-of-portlands-shanghai-tunnels/
bakersfield.com/news/the-legend-of-bakersfields-downtown-tunnels-truth-or-fiction/article_1e0428e9-68f7-5c1b-b27b-e0b914f61943.html
weirdfresno.com/2009/06/underground-tunnels-found-in-fresnos.html
latimes.com/archives/la-xpm-2007-nov-26-me-tunnels26-story.html