> The Stone of the Sun, now understood as a sacrificial altar.

Eh?

I still thought they couldn't figure out what it was for.

Hmmmm... It does say here that modern archaeologists think it was for sacrifices.

https://en.wikipedia.org/wiki/Aztec_sun_stone#History_of_int...

As an aside, a pet peeve of mine is when people in pop culture portray the Maya with the Aztec sun stone, or any other such confusion between Mayans and Aztecs. They lived very far apart! It would be like confusing the French with the Czechs!