I have checked the website for Who Built The Moon, and the answer appears to be time travelers. They also built the National WWII Memorial in advance, and GCHQ as a satellite dish to communicate with Stonehenge in the distant past. The Freemasons hold this sacred knowledge, which you can tell by squaring a circle and noticing that the ratio of circle area to non circle area is roughly that of earth radius to moon radius. Freemasons talk about squaring circles all the time.
Comments