Writing a Broadway themed epic fantasy novel series…need things to research

So in the aftermath of the Tony awards as is usual with most artists, I’ve become inspired to work on something. In this case for me, I’ve been thinking about writing a fantasy novel for a while that is centered around Broadway and the theatre world. I’m trying to do some research and I want to ask you all what’s one aspect of Broadway that not a lot of people know about but you do that would be perfect to incorporate into a fantasy setting…we’re talking secret societies, hidden rooms inside Broadway houses, little known facts about Broadway shows and stars, whatever it is, give me something that most people can’t find in the books

DurantPlummer41 said: "This is a fun little broadway "secret:"https://people.com/how-hannah-cruz-snuck-visits-with-husband-between-shows-exclusive-11988431


Yeah Ive definitely heard a lot about the hidden tunnels, will probably definitely work in a fantasy setting... I actually have all four editions of Jen's Untold Stories series, and I even have a more recent one History Hiding Around Broadway by Teale Dvornik (the backstage blonde)