Regarding important geographical sites of historic merit (and their modern memorialization)
One possible explanation behind modern Cooperation xB architectural stylings could be the very wreckage the Progenitors emerged from. As the point from which xB life crawled out of Cube 5219, the Cubesfall Memorial lingers at the "head" of their city, a place where entombment, vegetation, and time itself congeals over the cube's ruins, and the Cubesfall Outpost Massacre site stands as a parallel reminder to Hivemind-influenced violence. The Cubesfall Memorial is home three significant sites, and will be described as follows: the Cube 5219 Crater, the Queen 49 Plaza, and the Cubesfall Outpost Massacre ruins.
Cube 5219 Crater
Visible from space, the Cube 5219 Crater is the "topper" of the Cooperation's Capitol City in both cultural genesis and communal linkage to their past as Borg. Even though it remains forever broken, Cube 5219's ruins are still the largest artificial structure on the planet, even dwarfing the Reclamation Project's Headquarters. From the head of the Queen 49 Plaza, guests are able to descend the half-kilometer deep crater by stairs, incline, elevator, or transporter pad to enter Cube 5219's final resting place, the center hosting an eternal flame to provide seclusion and a private place of mourning. For all its jagged edges, the old support frames of Cube 5219's collapsed and scavenged decks hang open, exposed to the elements and drifting seeds of Ohniakan planet life: as if a giant had fallen, its ribs decomposing and merging into hills and cliffsides to nourish the life growing within it after its death.
Despite its crumbling-looking nature, the integrity of the support frames remain strengthened for one important factor: Cube 5219's center also holds the ever-shifting Wall of Entombment. Since Progenitor times, this place has woven itself in with xB funeral rites- where those close to a deceased individual bring and attach one implant into the instinctually kinetic structure of Cube 5219's ruins. The cube's remnant nanoprobes weave this resupplied augment in with its very hull, keeping the monument eternally stable and adapting to the wearing elements.
Regarding visitation, it is in poor taste for non-xBs to enter Cube 5219's core unless accompanied by an xB friend or family. This is considered revered ground for xBs, and unwanted visitors may stumble upon a gathered group to embed their loved ones' implants into the wall, or encounter a cloister of Progenitors meditating on their haunting past. For more facts concerning xB Funeral Rituals and Rites, see Chapter IV, Section 3: "Concerning Non-Species Specific Ohniakan xB Burial Customs," Paragraph 4. (ARCHIVAL NOTE: FUTURE MATERIAL TO BE PUBLISHED)
Queen 49 Plaza
Though Cube 5219's Crater is the Memorial's largest spectacle, the circular Queen 49 Plaza completed in 2379 offers its own place of congregation, connecting the Crater's entrance and Massacre site. Named for the self-immolated Queen that perished before the vessel's crash-landing, a weeping willow-like tree stands in the plaza's center that Queen 49 was buried beneath in 2368, Progenitors pulling her charred head from Cube 5219's Queencell in what historians call "Ohniaka III's first funeral." Behind this tree stands an obelisk, the 50 meter tall construct rising up from a visitor's perspective to perfectly match the highest point of Cube's 5219's hull from its resting place. I have been told there are urban legends that the deceased queen lived on as an xB inside the tree, Plaza-goers quietly joking that it's why "these branches sway with the exact same weight of a queen's hydraulics cables."
Surrounding the circular pavilion, large slabs taken from Cube 5219's hull are engraved with the designations of each drone lost before or during the initial crash. These massive pylons shimmer from the circular Borg script that litters their fronts- highlighted by the sun, as if the center obelisk was a great sundial. It is customary to leave tokens, offerings, or other items of remembrance at this plaza, even if visitors don't have direct relatives or loved ones inscribed in these walls. I have seen many things laid at the base of certain slabs: Ohniakan flowers, Vulcans meditating quietly with Katra stones, Earthen roses, and even an interned Bajoran prophet's prayer box regularly cycling incense that made the plaza smell vaguely of patchouli.
Cubesfall Massacre Site
To the plaza's left and encroached upon by Cube 5219's crater border, a solemn path and miniature plaza leads to a distanced view of the Starfleet outpost's ruins, standing as testament to the Cubesfall Massacre of 2368. Before Cubesfall, this outpost was a small Starfleet research center home to 30 scientists, exploring what made its atmosphere's ionizations so shielding to outside scans. Cube 5219 landing so close to this Starfleet base on Ohniaka III was no accident; as its submatrix began to collapse while pulled in by the planet's gravity, the Cube's collective consciousness locked onto this outpost's faint, cloaked signal as a last attempt to uplink with the Borg. These drones were pushed into further anguish once those aboard realized this was not the Hivemind's guidance they so dearly sought, the Queen that once directed their many voices already dead as the Cube streaked through the sky.
The question of "who fired first" is one that might not ever be answered thanks to the chaos of Cubesfall, but it is clear that this traumatic bloodbath weighs heavily in the minds of each Progenitor.
While it was vacated and burned during the xB Reunification as tribute to dismantling the android ▇▇▇’▇ influence, the foundations of the minuscule research facility still stand as a charred husk of tribute. It is forever closed to the public out of respect for the violence that occurred on the site's grounds, only visited by Progenitors and their students to ensure structural integrity of the ruins. The 45 xBs slain by Federation officers are commemorated by plaques on the ground leading up to the outpost where they fell before the Progenitors overtook this building. In return, the names of the slain 30 Starfleet officers are emblazoned on a podium, commemorated to the Federation during the signing of the Ohniakan Accords in 2379 (along with remains that were finally sent back and identified 11 years after Cubesfall).
It is a somber experience, visiting this site, and a rotation of volunteering xBs keeps watch over these Memorial sites. It is permissible to speak quietly at these great plazas, and guests are welcome leave items or other physical means of mementos in the Queen 49 Plaza to those they grieve in relation to the Borg. Many former Starfleet officers congregate yearly to memorialize the Battle of Wolf 359 or the Sector 001 Invasion of 2373, in lieu of possibly facing unwanted conflict in San Francisco. While these memorials are inherently mournful places to visit, they can also serve as reminders, to xBs, of the greater community they share. To quote my guide that escorted Junction Horus and I:
"We all have similar ‘impacts’ made upon us, from the Borg. And those sites will never really leave, much like these ruins. There will always be remnants; and that, inherently, is not a failing. It simply guarantees us that we will all share a constant in our lives. A constant all around us, that also shares these remnant impacts. That constant, Doctor, is Community... and a Community such as ours proves very hard to wholly eradicate."