6M of penetration in concrete, LOL.
https://www.youtube.com/watch?v=4H6WPXY3q7g

Chinese studies show how easy to divert.
https://www.youtube.com/watch?v=TriASB-F5UY

nuke proof engineered blast proof tunnel system.
https://www.youtube.com/watch?v=lrp9Tvv5wME