Installation 00

The Ark is an enigmatic Forerunner structure from which all the Halo Installations across the galaxy can be activated. In this final cutscene, Delta Halo is armed by Tartarus, but is then unexpectedly shut down by Miranda Keyes, causing it to send a communication, to all other Halos in the galaxy, putting them on standby mode, primed to fire. 343 Guilty Spark informed Miranda Keyes, Sergeant Johnson and the Arbiter that the Halos must now be activated or deactivated from the "Ark".

Ark on Earth
The exact location and characteristics of the Ark have not been released by Bungie, although, in the Halo 3 campaign and Hornet vehicle video, Keyes tells Lord Hood that the ark is fully uncovered, which could lead fans to believe that the Ark is in fact on Earth. In the wake of the Halo 3 announcement trailer and the clips on Campaign cut scenes released, along with Iris, it has been suggested the Ark is outside the town of Voi, or between Voi and New Mombassa, or suggested to be under Mount Elgon.


 * In Halo 2 the Covenant ship carrying the Prophet of Regret jumped into Slipspace, for unknown reasons, just a few hundred meters above New Mombasa. This caused the destruction of New Mombasa, and unearthed a huge Forerunner artifact seen in the Halo 3 trailer. The Halo 3 Announcement Trailer depicts a huge structure firing a beam of white energy straight into the sky, through the center of swirling clouds.
 * In the end of Halo 2, the conjecturally-named "Forerunner Ship", carrying the Prophet of Truth, jumped into Slipspace from near High Charity and Delta Halo, and for unknown reasons, voyaged to Earth, possibly towards New Mombasa, as the Forerunner Ship was headed towards Cairo Station, which is in geosynchronous orbit over New Mombasa.
 * Within the Halo Graphic Novel, in the short comic Second Sunrise Over New Mombasa, a transmission is intercepted between the Covenant assault forces stating that once the humans were dealt with in the First Battle of Earth, they would start uncovering the Ark.
 * In the real world, a concept sketch found in the Behind the Scenes DVD (seen right) names the artifact as the ark--more specifically, it names it as "Earth_Ark", which could suggest that the Ark is, indeed, on Earth, or alternately, could be a joke by Bungie.
 * In the Cradle of Life comic, the human N'chala is residing in Africa, and the "Gods" are building machines.
 * There is also, of course, the strongly supported theory that human life originated in East Africa, usually said as the Great Rift Valley. New Mombasa is in this area, so the Ark, supposedly, also is.
 * In the EGM September issue (leaked) on the page featuring the Hornet the text above mention that the UNSC is sending at convoy of Warthogs to clean up the Covenant air resistance at Voi to allow access to the Ark for Commander Keyes
 * In the cutscene where the Prophet of Mercy is attacked by a flood, the Prophet of Truth says: "The Great Journey waits for no one, brother. Not even you." According to the Prophets the great journey is equal to activating the Halos. In a cutscene later the Prophet of Mercy says that Truth is heading for earth to finish what they started: begin the journey and activate the rings, implying that the ark is indeed on Earth. However, Mercy's quote could mean the takeover of the planet.
 * Also, in the 2007 E3 demo, the Master Chief is shown in a warthog firing at something off screen, and with several wraith tanks in the background. Behind the 'hog is a large cliff, similar to the one seen near ark. The "forerunner ship" is seen in the background, possibly having landed in or near the ark. The scene is assumed to be in Africa, lending more credibility to the possibility of the ark being on Earth.
 * In the third server of the Iris VMC (Viral Marketing Campaign), the Log3_transcript text file held in it an extension of the quote from the video on the server:"Who has the right to live?/The light with the will to create me?/Or dark with the will to consume?" It has been suggested that the "light" described here refers to the Forerunners and the "dark" refers to the flood. This might indicate that the Forerunners are the creators of humanity and the ark is where we were released onto earth.
 * In the fifth server of the Iris VMC it was confirmed that the ARK was built to protect humanity from the Flood and the Activation of the Halos.

Again while the above evidence points to the structure in the Halo 3 Announcement Trailer being "The Ark", it has not officially been announced as such by Bungie, though Miranda Keyes refers to it as the Ark, so, it IS the Ark. And also in a leaked video of the final cutscene of Tsavo Highway, it shows that the Forerunner Ship has landed in the Ark.

Trivia

 * In the biblical story of Noah's Ark that was built to save Noah's family and a number of animals from a massive flood. This runs parallel to the Halo Universe story line where the Forerunner use the ark to save their species from the Flood. Also, in yet another reference to the number seven in Halo, the Noah's Ark story is in Genesis chapter 7|seven.


 * The real world Ark of the Covenant which according to the old Testament contains the stone tablets of the ten commandments, is the holiest object of the Jewish faith. The Ark of the Covenant is popularly believed to rest somewhere in east Africa, albeit in Ethiopia rather than Kenya.
 * The "Ark" seen in the announcement trailer is structurally identical to the Forerunner sanctuary described in the final chapters of Ghosts of Onyx (albeit on a much grander scale), complete with thirteen metal fins and a brilliant, blue-white portal in the ground. However, it is shown without the thirteen concentric rings rising around the portal, which means that it was either built without them or they will raise as the Ark opens. The ark could be another safe haven from the effects of the halos like the shield world. Also the ark could contain at least one Forerunner or pictures of them.
 * It is believed that the trailer took place around the levels of Tsavo Highway and The Storm.

Links

 * Halo.Bungie.Org's Ark forum.