A small trap door class opening to the Basement, located in the remains of the Osirak reactor in Iraq.
Iraq nuclear program was initiated sometime in the 1960s, but by the mid-1970s the decision was made to expand it through the acquisition of a nuclear reactor. After initial failures negotiating with the French and Italians, they were able to convince the French government to sell them an Osiris-class research reactor, a deal that included a smaller Isis-type reactor, 72 kilograms of 93% enriched uranium, and the training of Iraqi personnel. The sale was finalized by 1976, with construction of what became known as the Osirak reactor beginning 3 years later at the Al Tuwaitha Nuclear Center near Baghdad.
To this day it is strongly suspected by a number of the powers aware the Subterrestial Operations Theater that rogue elements of what became The Dédale Project were responsible for the reversal of the French position. Although the eventual requirement stipulated by the French that their personnel remain onsite for a decade following the plant going online seems a logical resut of Mossad's covert attacks on the project's infrastructure, detractors point to it as further evidence of duplicity. Naturally the French categorically deny this possibility, claim it is purely happenstance that the facility was contructed in an area of Fortean permiability, then blame the Americans for "bombing the site into the stoneage" to begin with.
On 30 September 1980 shortly after the outbreak of the Iran–Iraq War, Iran launched an airstrike on the site. Due to last minute concerns that the reactor had been already fueled and could release radioactive fallout if hit, they avoided the reactor dome and targeted the control room, research/centrifuge facilities, and the adjacent buildings including the plant's cooling mechanisms. The French and Italian technicians promptly withdrew and only returned in February the following year to repair the damage.
Although the engineers working on the Osirak project stated it was due to go online only towards the end of 1981, the Israeli attack on 7 June that year destroyed the reactor dome allegedly mere days before the project was due to be activated. Ten Iraqi soldiers and 1 French technician were killed, and although the French agreed in principle to help rebuild the site, negotiations to that end eventually broke down in 1984 -- the year before the oficial creation of Labyrinth. The Al Tuwaitha facility remained in its damaged state until it was finally eradicated by air strikes during the Persian Gulf War in 1991.
The Door OpensEdit
It's uncertain when exactly Jahannam opened — most of the personnel and documents relating to Iraq's Dungeoncrawling were lost during the 2003 invasion. Common conjecture is that while the French have a point and it was the '91 airstrike that managed to pop a small gateway through a serendipitous combination of brisance, fissionable material and natural permeability, the coordinated use of xenomethodology has to be a contributing factor. Whether it came before or after 7 June depends on what you think of the French.
Saddam Hussein's government were unequivocally aware of the breach and known to have named it and conducted at least one recon mission to the equivalent of 1st Landing by the end of 1999. The false information about the country's WMD programs used as the casus belli for Operation Iraqi Freedom was cover for the real reason for invasion: the prospect of "terrorists" having easy access to Dungeontech. Ironically, it would turn out that the massive expenditure of equipment and lives was ultimately futile as al Qadim quietly seized Orcus in Algeria out from under Dante's nose.
The realities of a secret war meant that before the unit LONGSTAIR had originally tasked to secure the site could be deployed topside, they found themselves on 3rd Landing repelling a sustained assault by the largest number of Oscars to date. As a result, conventional troops unbriefed on what to expect found themselves doing it. USCENTCOM literally had no idea what they'd walked into, only that it was really weird and they weren't sure what to do about it except keep reconning it while searching for something resembling a rational explanation.
The CENTCOM code phrase for the Osirak trapdoor was RABBIT HOLE, though the troops actually entering the Basement have taken to calling it the "Rabid Hole". Once LONGSTAIR established operational control after a week, the designation became its official US designation. A number of the soldiers who had ventured through RABBIT HOLE were subsequently reported as having been KIA as a result of hybridization taking place, while many of the others were redeployed as DOGs.