Lol!
People really still don't believe?!!!!
Here is a pic from the underground. I took this screen shot as a soldier when I had gone in with the chute. Check out the tiny little bridge as seen from below. As for the bridge access; the pic Martin posted shows the entrance that opens under the hangar once
both of the bridge sections under it have been bombed. (Martin's pick shows that the bridge had already repaired with him inside) There is time before the bridge repairs when you can get through if you hit it at the right angle, or if you parachute at the right spot your tank will spawn part way in part way out. If you're in just the right spot when you get in the tank you will be inside.
I want to try getting through with the d8 so I can fly around below. I've almost got the e111 before, maybe the d8 will fit.
(Come on guys, it's hard enough to find! Give the new guys a chance! Why does the Tunnel Club need to be kept a secret?)

I think some people think it's a joke and they claim to have been there when they haven't. Those people are giving false info and are just messing with you. Others have been there and don't want it to be easy to find.
Lol!