Where'd you get these images? LOL
There's caverns under the complex, yes, some water logged.
You can access these caverns from near the Sphinx compound.
Idk where you get silos and stuff, but from what I could see it was a mine.
What's the real confusing thing is that there are stone blocks bigger than the entrance to the caverns located inside the cavern, so no one knows how they got that in there