Photographer Davit Tabagari has taken hundreds of photos of historic underground shelters in Tbilisi, Georgia, only some of the traces of Soviet influence that can be found in the country. When he started exploring, Tabagari accessed some of the more than 400 underground shelters in the city by street level entrances that are still open but mostly unnoticed.
Check out some of his photos in this article from My Modern Met or visit his Instagram page.
Any of these could provide a story prompt or setting for a story. What happened in those shelters when they were new? How could they be used now? Does your story need an underground city in an altogether different milieu?