- "Banished from humanity, the machines sought refuge in their own promised land. They settled in the cradle of human civilization, and thus a new nation was born; a place the machines could call home, a place they could raise their descendants, and they christened the nation 'Zero-One'."
- ―The Instructor [src]
It was created long before the events depicted in The Matrix, when humanity spurned the machine desire to become partners of man (with the same rights and freedom). 01 became a prosperous and peaceful city, selling goods to humanity's countries such as the innovated hoverpad and commercial air-vehicle, Versatran. It is located in the Cradle of Civilization, Mesopotamia, aka the Fertile Crescent.In almost no time, 01 quickly became the leading global superpower. Man's economy lost revenue and, as a result, power. 01's ambassadors pleaded a co-existence with humanity to the United Nations, but were denied. They used nuclear weapons in an attempt to destroy 01, and thereby eradicate machinekind. These weapons proved to be ineffective against the machines. War machines developed in 01 advanced throughout the world, invading human nations. In a desperate attempt to rid the machines from a power source, humanity led the scorching of the sky and in result the downfall of man.
Without human intervention, 01 has grown to tremendous size. It runs on a combination of nuclear fusion and neuro-electric energy generated by the billions of humans in its power plants, which are connected to the Matrix. Surrounding the city is an immense defense system consisting of large, crablike Defenders that activate when unauthorized craft approach.
The central part of the city houses the mainframe computer Deus Ex Machina, which controls all machine activities. Neo confronts the mainframe and forges a truce in exchange for stopping Smith from spreading like a virus.
The city's name refers to the binary code inherent in all computer programming after the human readable language has been translated into 1's and 0's.
Once Neo has defeated Smith at the end of Matrix Revolutions and is carried away, the glowing eyes of the machine carrying his body away are green, not red like the eyes of the others. Additionally, some of the lights in the city in the background have changed from red to green, reflecting the change in the machines.