This question has been batted around for a lonnnnng time.
Several ‘reasons’ have been suggested including sickness, bad crops, etc.
Likely we will never really know the complete answer as to why the pyramids and cities of the Mayans were deserted.
But, recently an article was posted on the internet with another idea as to why the Maya left the Yucatan, Mexico area.
Thought you would be interested in the latest ‘idea’ plus the pictures and the general information is definitely worth a look, so HERE’S THE LINK.