Original: Initially established during the Pre-Classic period ( c. 2000 BC to 250 AD ) , according to the Mesoamerican chronology , many Maya cities reached their highest state development during the Classic period ( c. 250 AD to 900 AD ) , and continued throughout the Post-Classic period until the arrival of the Spanish .
Simplified: The remains of this city are thought to be below the modern city of Flores , Guatemala on Lake Petén Itzá .