The Mayans dominated Central America for 12,000 years. They lived in modern day Southern Mexico, Guatemala, El Salvador, Belize, Honduras, and Yucatán Peninsula.
The Mayans created the number zero. If they haven't created the number, we would probably still be on roman numerals like England until someone made the number and place holder. We wouldn't be able to calculate things properly without the number zero.
Theories as to why the Mayans fell from power
The Mayans had a very advanced math system. They were far ahead of England who were stuck using the Roman Numerals. They could calculate things much better than England could.
Which theory I believe about how the Mayans fell
The Mayans were very skilled architects and created structures with great precision. They're structures were very precise and created the effect of a serpent going down the structure when the sun moved positions.
Theory 1: Warfare Theory 2: Disease Theory 3: Famine Theory 4: Disaster or Environmental Change
Disaster or Environmental Change
I believe that Warfare or Disease brought the Mayans out of power because they could've been driven to flee by a more powerful source. Disease could also be an option because they didn't have as advanced medicine as we have now so if they did get yellow fever they wouldn't be able to treat it properly.