https://inexplicata.blogspot.com/search?q=The+Tunnels+of+the+Americas
https://www.imdb.com/title/tt0060036/mediaviewer/rm3013509121
https://unchartedruins.blogspot.com/2018/07/the-secret-tunnels-of-ancient-mexico.html
"During the California heat wave of 1906, Baldassare Forestiere dug a home underground with just a pickax and shovel. He spent 40 years excavating 10 acres of rooms..." https://www.youtube.com/watch?v=mUKRPoQKynk Quite a nice, do it yourself underground complex.
Coober_Pedy, Australia https://www.youtube.com/watch?v=MCXnKgSr1N0 , https://en.wikipedia.org/wiki/Coober_Pedy#Tourism , https://www.youtube.com/watch?v=ihn-jWnOWwI
"The Krell machines in Forbidden Planet are a vast underground computer complex built by the advanced but long-vanished Krell civilization." https://www.facebook.com/groups/forbiddenplanetmovie/posts/10163715398958777/
https://themoviejunkie.medium.com/the-forbidden-planet-retro-futurism-at-its-best-d58cb42e76fb
https://nzpetesmatteshot.blogspot.com/2011/03/forbidden-planet-shakespeare-in-space.html
And more not so ancient stuff.
https://www.reddit.com/r/RetroFuturism/comments/115igaw/the_time_tunnel_1960s_tv_show_time_machine , https://www.imdb.com/title/tt0060036/mediaviewer/rm413040641
A documentary about the classic 60's Sci-Fi series 'The Time Tunnel'. https://www.youtube.com/watch?v=3MByhY6aSUo
It all started deep, down in the desert...
https://www.facebook.com/groups/classic.television.shows.group/posts/1436470110334314/
https://en.wikipedia.org/wiki/Underground_city
Underground Tunnels and Cities https://www.youtube.com/watch?v=g8V2u7YT02w
https://en.wikipedia.org/wiki/Path_(Toronto)#Early_pedestrian_tunnels
https://en.wikipedia.org/wiki/Subterranean_New_York_City