It is amazing, isn't it? I mean, just trying to wrap my head around the scale of those glyphs is just impossible. I am aware of the existence of the lines in the Mojave, also. I prowl around quite a little in this part of the world.

I mostly look at petroglyphs. We have some here in Yuma that are over 7' tall and pretty badly faded, means they are old. One of my favorite places is a place called Painted Rock about 70 miles east of me. It's a graffiti pile of petroglyphs. They tell us most of them were made by a people that left about 900 years ago. There are other, older abandoned sites around here too. Where did they go? A huge mystery.

Painted Rock is associated with the Ho Hokum who built Casa Grande. That two story building has an interior room with a window that only passes direct light on the summer solstice. I have camped at Painted Rock for both equinoxes and solstices, some of those glyphs seem to be time sensitive, with shadow lines in travel wheels and such. It just amazes me. The people at PR had a really extensive irrigation system in place and obviously grew crops there. I have a hard time figuring how they got the water to flow when they didn't even have a level. I'm guessing that they used a pot with a line etched on the inside, filled water to the line then set their angles with that, but nobody knows.

I could go on :) Thanks for pointing out that documentary. I haven't seen it in a few years, I'll watch this afternoon when things slow down (he says optimistically).