I adore behind-the-scenes tours. I get there's a lot of work that goes into making it happen, but when you drop into a place where people work, you'll learn so much about real life problems that never make it to the Internet. The greatest tour I ever had was at the Smokejumper base in remote WA. At any time when they're open, you're allowed to drop in for a tour and whoever is there that day is obliged to give you on…
I highly recommend the tour of the Itaipu Binacional hydroelectric dam in Foz do Iguaçu, Brazil (well, it's also in Ciudad del Este, Paraguay, but the tour starts from the Brazilian side). https://turismoitaipu.com.br/en/ Get the "special tour" which takes you inside the dam. An absolutely incredible spot and incredible achievement. They will take you into a room with a turbine shaft that's mechanically transmitting…
Expect potential weirdness though. My wife was wearing a (not particularly short) skirt, and the lady at the office selling tour tickets made her step back and spin around, then said she couldn't go in like that. There is a gift shop that sells dam branded pants, so she bought a pair and we were cleared to go in. After all that, one dude in the control room was watching soft-core porn on one of the control room computers.
The turbine shaft room is especially crazy, since they let you (at least back then) walk right up to a few inches away from the shaft mechanically transmitting 700 MW of power! You could reach out and touch it, but we didn't and I wouldn't recommend it.