Conversation so far:
Anything interesting in 2000BC or near that time with the Maya civilization?
The Maya developed their first civilization in the Preclassic period.
Did anything happen in AD with the Maya civilization?
The Late Preclassic cultural florescence collapsed in the 1st century AD and many of the great Maya cities of the epoch were abandoned; the cause of this collapse is unknown.

Question: What happened when it collapsed?
Self-contained rewrite: What happened when the great Maya cities of the epoch collapsed?