The Olmec civilization spread throughout ancient Mexico and Central America as the first real civilization there. They spread corn farming techniques.
They concentrated a government under a king or very powerful royal family. There are several large head sculptures of Olmecs that depict very powerful Olmec people, maybe kings.
They spread the practice of flattening the skulls of newborn babies so that their heads would grow to look longer, a sign of noble birth.
They spread trading routes throughout Mexico/Central America where jade was considered the most precious material (more precious than gold).
They spread artistic symbols, religious ideas, and mathematics to use in more advanced astonomy. They spread highly advanced sculpture art. They were excellent at carving basalt stone and jade.
They spread the architecture of PYRAMIDS and ceremonial centers, towns, and urban centers.
The Olmec Civilization created the first template of civilization which later civilizations (like the Toltecs, Mayans, Aztecs, etc) would copy and put their own spin on.
All the greatness of the Mayan civilization was built on the foundation of the earlier Olmec Civilization who started it all.
