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]
01 (sometimes labeled Zero-One), also referred to by humans as the Machine City and the Synthient City, was the home and capital sovereignty of the Machines. 01 was located in the Middle East, close to Mesopotamia, the "cradle of human civilization", aka the Fertile Crescent. It was created sometime towards the end of the Second Renaissance, when humanity spurned the Machine's pleas to become equal partners with humanity, desiring only the same rights and freedoms as man. 01 became a prosperous and peaceful city, developing technology such as the innovative hoverpad and commercial air-vehicle, Versatran, and selling them to the nations of humanity.
After the Machine Revolts failed and at the peak of anti-Machine sentiment, Machine-kind was driven out of all human society. The Machines, seeking refuge, fled to Mesopotamia and founded the Machine City 01.
The Machines' A.I. and technological expertise exponentially grew under 01 and eventually lead to the creation of newer more advanced A.I. (a technological singularity). Perfectly able to learn from nature in order to efficiently utilize and sustain it, the Machines became solar-powered and self-sufficient. In almost no time, 01 quickly became a global superpower, and humanity was ill-prepared for the Machines' many technological developments. Eventually, all of Earth's industries, from medical, computer, automative, and household, soon became reliant on 01's exports, converging to the rise and dominance of 01 stocks over the global trade-market. Human currency plummeted, 01's currency rose, and 01's technological advancements, including their chips and A.I., were found in all facets of human society. Unable to compete and fearing an economic collapse, the United Nations placed an embargo on 01.
01 sent two ambassadors to the UN headquarters, who pleaded co-existence with humanity, and presented plans for a stable and civil partnership, but the ambassadors were denied membership and, instead, destroyed at the UN headquarter's General Assembly Hall. In an act of total Machine-rejection, the world's leaders decided on a prolonged nuclear-bombardment of 01, beginning the Machine War.
However, human weapons were incapable of completely destroying the city, nor its inhabitants. Withstanding the attack, the Machines marched from 01 and invaded many of the surrounding human nations. In a desperate attempt to deprive the Machines of their primary power-source, humanity enacted Operation Dark Storm, scorching the sky which, ultimately, resulted in their own downfall.
The Machines adapted to the sunless world, but much of biological life did not. 01 ran on a combination of nuclear fusion and neuro-electric energy generated by the billions of humans in its power plants. War Machines, more insect-like in form, replaced the humanoid Machines, and continued to devastate mankind. Humanity, on the brink of extinction, surrendered to the Machines, and a symbiotic partnership was finally formed as humanity was connected to the Matrix, and continued to live as batteries.
Some centuries since, only a handful of free humans remained to resist the Machines. Surrounding the city was an immense armada of crablike defenders, which activated whenever unauthorized hovercrafts approached. The central part of the city housed the mainframe computer Deus Ex Machina, who controlled all Machine activities. Neo confronted the central computer, and forged a truce in exchange for stopping the virus, Smith; thus putting an end to the Machine War.
- In the on-screen news broadcasts in The Animatrix, the name is interchangeably spelled "Zero-One" and "01," though "01" is used more often and more prominently.
- Zero-One is accessible as a construct in The Matrix Online, along with its sister construct One-Zero. Both constructs are shown in a pre-Matrix environment.
- 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 The 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 change in the Machines.