The labyrinth may be under that courtyard at 1:08. If so then why the pyramid? They pump and purify water and put out a field that could protect the ones in it. The intense heat event that Brien talks about could have been the reason they built the underground complex. I heard there's 3,000 rooms. I also heard a story of the Ant people/Greys taking Native American Indians into an underground system for a time possibly to protect them from the same event. One theory I found interesting is the angular momentum the planets exert on the sun twists its magnetic bands and a point is reached where they spring back to normal expelling a micro-nova.
