A major step in the development of civilization was?

A major step in the development of civilization was the agricultural revolution. And the infrastructure of water supply and sewage disposal. And the transportation revolution: harbors, canals, roads, rails, air. And the industrial revolution: stages of invention, innovation, growth, decline; systems: The American System, Assembly Line, Just-in-time. Then the communications revolution driven by electricity: telegraph, phone, radio, television and the computer.