Thanks for rising an interesting point.

Research the geography of San Marino and Monaco including the ground below it.

Not easy to dig in stones. I understand the tunnels built for communication, using mine workers, TNT and special drilling heads used, but it’s usually a huge project.

A storage for content of 600 planes? That’s way bigger.

How many planes would fit 1 tunnel?

How many more tunnels needed?

Imagine the scale of it. Does it still look real? Or 600 is just a mistake.

Thanks for rising an interesting point.

Research the geography of San Marino and Monaco including the ground below it.

Not easy to dig in stones.