Old Mombasa (Earth-5875)

Old Mombasa was an old sector in Mombasa, Kenya, on Earth, with all municipalities within a 74-kilometer radius of New Mombasa being considered a part of it. Unlike its sister-city, Old Mombasa was dilapidated and housed smaller houses and buildings, while focusing much more on industrial complexes.

Early history
During the Global Warming Pandemic that began in 2104, the sea levels of Old Mombasa started to rise, and thus Mombasa was forced with to build flood control measures so it would not flood and its citizens die. It was eventually agreed that it would be easier and cheaper to construct ports on the Kenyan mainlands instead of shoring the old docks, leading to the creation of large seawalls and dams to hold the water back, with better and improved docks being extended to Kilindini Harbor.

Development
The docks brought the much-needed prosperity to the city, with the once poor villages and towns being replaced with buildings and highways, leading to a new thrive in commerce. With the end of the Epidemic in the late 22nd century and the focus on interstellar colonization with the discovery of the slipspace, new technologies arrived, which helped millions of humans who inhabited Earth to depart to other planets under the government of the UEG, helping to decrease the sea levels and high temperatures once more. However, this meant the massive dams had no purpose whatsoever.

With its increasing economic stability and strategic localization, New Mombasa became the busiest sea port on Earth, and in 2302, it was chosen by the Unified Earth Government to be the first city to house a space elevator. This elevator, the Mombasa Tether, only served to increase New Mombasa's economy, and the city became one of the most important locations on the planet.For the next eleven years, New Mombasa saw a huge economic growth, as well as a large influx of trades, job changes, and citizens, which came to drastically alter the appearance and landscape of the entire city, something which spread to the country and the African continent. The older buildings that still occupied the sights were replaced with large buildings and entire industrial complexes.

By 2430, New Mombasa had grown to the point of absorbing the entire Mombasa island, as well as nearby settlements and towns, which became unofficially a part of Mombasa. Not long after, it was decided that all municipalities within a 74-kilometer radius of Mombasa were referred to as "Old Mombasa". By the 26th century, New Mombasa was known for its cosmopolitan features and dynamic landscape, featuring mile-long suspension bridges, highly efficient maglev systems, automated highway networks, a well-equipped, and well-organized police department, massive recreational areas, natural reserves, and parks. The city was organized into numerous symmetrical and numbered sectors, with districts of old still existing, such as Kizingo and Kikowani, Tangana, and Mbaraki.

Battle of Mombasa
On October 20th, 2552, the Covenant Fleet of Sacred Consecration, under the command of the Prophet of Regret arrived on Earth from slipspace, and a battle soon ensued. During the engagement, Regret's flagship, the CAS-class assault carrier Solemn Penance, breached Earth's orbital defenses and moved to New Mombasa, sending warriors and vehicles to occupy the city in the search of a forerunner location the fleet had previously discovered through a Luminary on Meridian following its glassing months before. Many civilians were immediately killed by the deployed warriors, although some managed to escape and be evacuated. Swahili announcements about the attack were broadcasted in both New and Old Mombasa, warning the citizens to follow the evacuation efforts of the UNSC Marine Corps and the NMPD. Some of these announcements even claimed false information to boost the morale and give hope to the dying citizens, some encouraging citizens to fight back against the "alien zealots".

The same day, John-117 was deployed on Old Mombasa to rescue civilians and assist UNSC Marines in pushing the Covenant back from the city. After killing many enemies in that portion of the island, he crossed the Kilindini Bridge and reached New Mombasa, where the SPARTAN-II was able to board a Type-47A Scarab that had previously killed countless of UNSC forces, and later returned to the UNSC In Amber Clad. During the confusion, the Prophet of Regret had the Solemn Penance prepare to leave Earth out of desperation, leaving all of its land troops behind. At the same time, sixty ODSTs were dropping from the UNSC Say My Name into New Mombasa to breach the carrier. One such squad, Alpha-Nine, however, had secretly been re-purposed by the Office of Naval Intelligence to drop into the Alpha Site and secure Vergil to prevent it from falling into the Covenant's hands, which remained in secret until they were in mid-drop. With the sixty ODSTs descending, the Solemn Penance unexpectedly jumped into slipspace as the In Amber Clad pursued it, with the resulting EMP destroying the surrounding buildings, heavily damaging the Mombasa Tether, and disintegrating all ODSTs with the exception of Alpha-Nine, who were accidentally saved by their last minute redirection to Alpha Site.

Not all of New Mombasa was consumed in the explosion, while those that did were sucked into slipspace; the rupture created a gigantic crater in the mainland of the island, where the Covenant later arrived to start digging the Excession. Following this event, the jiralhanae that remained on the city were ordered by the Prophet of Truth to carry out his secretly plotted genocide against the sangheili who were also left behind, leading to massive civil battles. The jiralhanae, who were at their most numerous, gained the upper hand, and killed all present sangheili, alongside those who decided to remain loyal to them. These jiralhanae troops also continued carrying Regret's excavation of the Excession, being ordered to capture Vergil and Quick to Adjust, the huragok who was able to free from its slavery and fuse the artificial intelligence's data with its own. This led the UNSC and the NMPD to fight together against the Covenant for the rest of the day. In the next day, the Fleet of Certain Fulfillment, led by Truth himself, arrived on Earth and started to glass the city in search of the hidden portal. Alpha-Nine, one of the only survivors of the event, managed to secure Quick to Adjust, and thus Vergil, escaping the city in a stolen Type-52 Phantom.