Secret tunnels? Vaporeon approves 
@vaporeon_ do you know anything about avatar: the last airbender?
@wallhackio No, not at all
I was thinking of guerilla warfare, like that Vietnamese tunnel system and like the Hamas tunnels
@wallhackio Tell me about that airbender
@vaporeon_ it's one of the classic children's cartoons from when I was kid. it had a bit of a renaissance a few years ago because Netflix added it to their lineup. It's very good
@vaporeon_ Extremely anime-esque despite being produced in the west, which was unusual in 2008 (not that weird anymore, anime is cool now).
I just tried to write a summary but the show's opening is a better summary than I could ever write: https://www.youtube.com/watch?v=LOWBBMC__w0
If it looks even remotely interesting to you you'll probably like it. It's one of those shows that just about everyone will like
