Aperture Relic

The Aperture is a Forerunner relic mentioned numerous times in Covenant holy scriptures, though the most detailed accounts were considered apocryphal by the Prophets until recently, their authors deemed to have misunderstood the original meanings, or worse, declared as Heretics by the Covenant and their works burned to destroy the "heresies" they contained. It is ironic that in their haste to begin their Great Journey, it is to these heretical works that they turned to in the end.
The most detailed surviving account is found in The Satsunaran Prophecies, a collection of the lives work of Tano 'Satsunar, a self-described Sangheili "seer" of the Forerunners, who claimed to derive his knowledge from holy sources. The veracity of his claims has never been confirmed, though some Kaaranese historians suspect that he came into possession of a Forerunner relic and managed to translate a portion of its contents before he was driven mad. His account of the Aperture, however, is extremely detailed.
In it, he describes a thick central structure with extensive internal corridors going deep underground, ringed by six inward-leaning pillars. These pillars are supported by thick beams at the base, attached to the central tower at approximately ground level, with energy tethers connecting the beams to the tower. This description is surprisingly accurate for a semi-religious figure who lived fourteen hundred years ago and never saw Earth or the Aperture relic, and is one of the reasons why his works are being given a more attentive glance by Sangheili scholars.
Exactly what the Aperture is, the Prophecies says little, mentioning only that it is a gateway, comparing it to a "window" or "door," and even then the author still refuses to elaborate on what lies beyond the "door".
During the Second Battle of Earth, the Covenant spent a considerable amount of time and effort trying to locate relics elsewhere on the planet, including in the seabed off the Yucatán peninsula and underneath Mount Erebus, but the only major known relic found was the Aperture, underneath what was once Sydney, a major city in Australia. After capturing the continent and driving out the UNSC defenders, a small Covenant taskforce set to work demolishing the centre of the city and uncovering the relic as the rest of the local forces set up defences. The actual excavation was remarkably quick - while the Ark Portal was more than a dozen kilometers across, the Aperture was significantly smaller than that, only one or two; and even after the entrance had been excavated, the majority of the structure remained underground. The relic was activated soon after the UNSC and Sangheili began a counterattack on the continent, and by the time they had reached as far south as Sydney most of the Covenant ships and personnel had already passed through the small slipspace portal generated by the relic, leaving only a handful of defenders. After the site was secured, the UNSC/Sangheili strike force followed the Brute ships in pursuit, and the relic was secured by later UNSC forces from the African theatre.
After the war, the relic was cordoned off and an Office of Naval Intelligence field operations site was established to study the relic. The internal corridors were mapped out extensively, and much of the technology present was at least documented - full reverse-engineering would be impossible until UNSC scientific understanding could catch up to the sheer sophistication of the Forerunner technology, though acquisitions from the Sangheili and scavenged Covenant technology would prove helpful in the cateloguing of it.
== Quotes ==
* "The thing is tiny when compared to the New Mombasa structure, but its portal is about the same size - now how does that make any sense? It makes me wonder just what else the other site is hiding within it..."
* "The most I ever read of it in my studies was that it was a metaphor for the importance of self-reflection. The Prophets kept many things secret, but even they never thought that a "heretical" text could contain the keys they needed to unlock their Great Journey."
* "Find the Labyrinth, and stop the Journey!"