Zion (The Matrix)

Zion is a fictional city in The Matrix films. It is the last human city on the planet Earth after a cataclysmic nuclear war between humankind and sentient Machines, which resulted in artificial lifeforms dominating the world.

History
Following the United Nations attack upon the newly-established machine civilization of Zero One, a global nuclear war between both factions began for control of the Earth. After several desperate plans to halt the seemingly never-ending waves of techno-soldiers, the human leaders realized that the Machines had a good chance of winning. The human leaders began the construction of an entirely underground city, called Zion, that was built for the purpose of preserving the human race. When the war ended in the Machines' favor, the remnants of humanity were left struggling to survive on the cold, dangerous and desolate surface. It was quickly becoming uninhabitable due to the cloud created by Operation Dark Storm. The Machines captured or killed almost all humans with the exception of the inhabitants of the unfinished Zion. The captured survivors were imprisoned and put into the newly-constructed bio-electric towers with their minds placed in the Matrix to keep them docile. Twenty-three prisoners were freed by a mysterious Matrix-controlling figure referred to as "The One" and led to the unfinished Zion where they worked to complete it. After making the city operational and regaining technological usage from geothermal energy from the Earth's core, the One taught the humans to continue building and maintaining a war effort, and to fight inside and outside the Matrix. After the One's death, the humans learned to survive on their own and began waging a partial-guerrilla war from Zion against the Machines, and at the same time trying to free the Matrix's population from their virtual "prison".

Geography
Zion was built four kilometers below the Earth's surface, just above the Earth's mantle, and exists entirely underground. The city itself is cylindrical (vertically inclined with respect to Earth's surface) in design and possesses many levels including:
 * Council Chambers: This level is near the bottom area of the middle section of the city. It has a series of chambers that are used as living areas and offices for the members of the Zion Council.
 * Gathering Spaces: A level just below the Dock. It contains many areas where homeless or new arrivals rescued from the Matrix gather to live until permanent quarters are assigned.
 * Geo-Thermal Generation: This level is near the bottom of the city. It is dedicated to providing power to the city in the form of geothermal energy from the Earth's core.
 * Intermediate Areas: Other areas of the city that have yet to be mentioned and only seen.
 * Life-Support Level: The bottom level of the city. It is dedicated to providing life support, in the form of water, warmth, air, etc., to the city's population. In an ironic twist, the machines that do these tasks are entirely automated, but their human overseers have taken steps to ensure they can never reach sentience, and the machines have built-in kill switches that would shut them down at the first signs of sentience.
 * Living Quarters: The entire central middle section of the city. This level is dedicated to providing shelter for all of Zion's population, numbering approximately 250,000.
 * Meeting Hall: A chamber near the bottom of the city. This is where the Council convenes and meets with Zion's hovercraft Captains and military leaders and plans high-priority missions.
 * The Dock: The top level of the city and entrance into the underground tunnel network. The dock is operated and its systems administered by the operators in The Crane Tower. It provides a recharging station and repair area for the hovercraft fleet.
 * The Temple: A large cavern below the city itself. This cavern is dedicated to holding religious gatherings for the entire population, and also serves as a last defensive position in the event of a complete invasion by the Machines.

Defenses
Zion has a multitude of defensive systems that collectively is commonly known as the Zion Defence Grid. The systems consist of:
 * Six Double-Barrel Turret Machine Guns: The main defensive system, installed in The Dock, which serves to protect incoming hovercraft from Machine incursions.
 * APU Corps: Mechanized bipedal combat suits that are used for heavy support in the event of an attack on The Dock by the Machines. The corps is led by Captain Mifune.
 * Infantry: Human soldiers equipped with electromagnetic "lightning" guns plus rockets and launchers. They are trained to defend the city in the event of a Machine incursion.
 * Hovercraft Fleet: Electromagnetically powered hovercraft that continuously fight the Machines in the real world with EMP weapons, with crews fighting to free the Matrix's captive human population by journeying into the Matrix itself.

EMP devices, despite being installed on every hovercraft in the fleet, were never installed in Zion's defensive grid (even as a last resort), primarily because the city possesses no EMP shielding. Though an EMP could be used and every Machine in its range instantly disabled, the defensive grid, APU fighters and virtually every piece of defensive hardware in Zion would be permanently disabled as well, leaving the city with no way to defend itself during a second Machine incursion.

It was later revealed that none of Zion's defensive systems were sufficient to withstand the juggernaut of the Machines' army. The city's total destruction and the death of its entire population was well within the Machines' power, but was never carried out due to their purpose (see below). An attack could have been ordered on the city at any moment by the Architect when he wanted to reload the Matrix.

Leadership
The city is governed by the Zion Council, which makes all administrative decisions for the city and the war effort. Other officials were recruited to report directly to the Council and carry out their orders on their behalf, including (reluctantly) the supreme commander of the Zion Defensive Forces; Commander Jason Lock. The captains of the Zion Hovercraft Fleet also have strict access to key data in the Zion Mainframe, and have political bearing with the population. Over half of the council is female, and over half of it is non-Caucasian, with Haman being the only white male on the council.

Purpose
Zion was initially built for the purpose of saving the last of the human race following the war against the armies of Zero One. However, a Machine program named The Architect, the creator and manipulator of the Matrix, manipulated the situation so Zion served as a control for the survival of the program in two ways. Firstly, the Machines could allow any humans who did not, or could not, accept the Matrix for what it was to live in the physical world without having to recapture them (this reduced dissent within the Matrix's population and prevented an exponentially-growing rejection rate from its population from causing entire "crops" of humans to die out, reducing power output). Secondly, the Architect would periodically destroy Zion and its inhabitants as part of a deal coercing the One into reinserting the "Prime Program", a program code required to maintain the Matrix, allowing the Matrix to continue and Zion to be rebuilt by chosen survivors without memory of the destruction. This cycle was broken when the sixth installment of the One refused to re-enter the program, and instead brokered the truce with the Machines.