Leviathan attacks a submarine

A great ocean leviathan closes in upon a nimble strike submarine emerging from a deep ocean trench. Leviathans were highly territorial and were driven into a rage by certain frequencies; before this was eventually discovered, many vessels were lost. 

Last voyage of the ocean freighter SS Phoenix

When The Apocalypse struck, all shipments of fuel and supplies ceased. Those with fusion stack engines were capable of operating almost indefinitely, and still ply the oceans to this day as mobile statelets. 

Ships still powered by fossil fuels used what remained to reach more temperate zones, or isolated islands where they could flourish, far from the chaos, mass famine and war that engulfed the continents. 

Ships that were unfortunate enough to have little fuel were stranded in situ, but they were often more secure than anything on shore, and became living communities, refuges for survivors and civilization. 

Arctic climes became even more inhospitable during the long nuclear winter, but on the positive side, the hostile environment and remote location kept them safe from bionitic horrors that overran more hospitable regions.

Above we see the ocean freighter Phoenix, once under the flag of Costa Rica. When The Fall occurred, it was outside the port of Vancouver. Rather than fleeing south or to the islands, it headed north, to Alaska, where the families of most of the crew resided. It later became the home base for two Russian nuclear submarines that had defected during the last organized conflict of humankind for a thousand years.

Sea Dredger Minos

The 50,000 ton bionitic sea dredger Minos off the Atlantic seaboard, hovering over a clutch of leviathan eggs. These could hatch up to a thousand young, making early interdiction vital for the local fishing industry. 

The Minos was used to scoop out channels for undersea communities, transit tubes and cables. Powered by a SD-400 fusion stack and bionite organic processors, the Minos was capable of operating indefinitely. It could even lay 'eggs', preferably in wrecks plentiful with both metallic and organic matter, that would eventually grow into a new iteration, linked by comms and shared operating systems. 

This image was created last year (before I cancelled my account) in Midjourney v4, then modified in ProCreate. 

Cyborg Dancers of Shomm

The iconic cyborg dancers of the Shomm Circus perform the ritual Purification Dance that grew out of the complex decontamination processes world populations became accustomed to in the Post-Apocalypse. 

It was eventually fetishized and incorporated into religious ceremonies.

The cyborgs of Shomm were ancient beings, who originally merged with machine in the dark early days after The Fall. They would eventually augment their physique with anti-gravity pods and enhanced limbs, allowing them to achieve dance moves of unparalled elegance and beauty. 

Here they perform for the royalty of Arcology Seven, shortly before the infamous Jandoreal Rebellion.

This image was created in Midjourney v4, then modified in ProCreate.

Astronauts of the Great White North

Temperatures in Alaska during the nuclear winter could drop to -90 degrees or lower; inhabitants would only venture outside wearing spacesuits with internal heaters powered by atomic decay diamond batteries. 

Seen here is the IEVA (intra/extravehicular activity) Ferron IV protection suit, with bionitic 'lungs' growing out of the back pack. These allowed for an almost infinite oxygen supply. Diamond batteries provided heating; radiation shielding was kept but the liquid cooling system was stripped out to save on weight. 

It was equipped with IR view, headset comms and survival gear kit, including flares, signal mirrors, flares, fusion cutter and emergency rations. 

The Ferron IV lacked a powered exoskeleton, but was made of durable, light weight materials, allowing it to be comfortably worn for extended periods.

The deadly catacombs of Post-Apocalypse New York

A beautiful Crimson Priestess delves into the dark catacombs beneath a rubble temple in former upstate New York, seeking survivors… only to find they are mutated beyond all recognition, and ravenously hungry. 

Underground shroomfarms and survival arcologies, vast interconnected chambers powered, and lit, by regenerative fusion pods, allowed for surprisingly large populations of troglodytes and a vibrant subterranean ecosystem. 

The genetically engineered Sunshroom, which grew rapidly in moist environments, was loaded with vitamin-D, negating the need for supplements. 

Bathing in the light of the fusion pods provided just enough to ward off atherosclerosis, diabetes and stroke. 

Towers of the Post-Apocalypse

Tower homes became popular with the proliferation of macro biological weapons, such as spike wolves and virus zombies, which made dwelling at ground level hazardous. Initial zombie infection waves scaled exponentially, resulting in highly over crowded tower tops. 

But their real estate evaluations went up, along with property taxes. Cell reception was also excellent, at least in regions where it was powered by hydrodams.

Towers used drones and robot retrieval systems were used for sourcing supplies, and when these were not available, the most agile and disposable inhabitants were.

Eventually, walls were constructed, and cities, now vastly depopulated, became warrens of walled off enclaves, fighting over hydroponic pods and the automated food factories.