Experts are divided on what color skin the Incas had, but we know they invented geopolymers that poured like concrete. (lemmy.world)
Edit: Cropped the image. The last person said a few crazy things but overall they were making a good point, so I thought better of including it.
![](https://kbin.life/media/cache/resolve/entry_thumb/ba/b1/bab13883107499c27bb2a8b704f2dc68ffc80d3f63e83db38651c467c6f3dce8.png)