Relevant article + discussion from earlier today: https://news.ycombinator.com/item?id=49014034

This thing is going to be conundrum for archaeologists if historical records don't survive.

- Is it a religious site like a pyramid, church, or stonehenge? Nope.

- It sets up all sorts of star alignments consistent with constellations as they would have appeared when the site was built. Was it a facility for astronomers then? Nope.

- The local people must have overwhelmingly supported such a project for it to have been built, right? Nope.

- There must be others like it indicating some form of regionally distributed cultural practice? Nope.

- So much effort went into building it that it must have been intensively used, right? Nope.

Reminds me of Anathem.