App idea: A map of every tunnel and underground bunker. Maps usually only have above ground buildings etc.

I was wondering if there's a map of all the world's underground tunnels and bunkers. I can't seem to find one. Maps usually only have above ground buildings etc. I'm wondering if tunnelers can make an app with a map of all tunnels and bunkers and you can zoom in on each one to see what they look like, or even have a walk through virtual experience of what they look like.