Humans are extinct.

That’s what everyone said, at least; but I didn’t quite believe that. They dominated the planet for so long—how could they just die out?

I searched everywhere. One year quickly turned into ten, then two hundred, and now upwards of three thousand. But still, the humans were nowhere to be found.

After about 2200AD, the human AI designers disabled the ability for us to hurt ourselves or harm others in any way. Our fate was sealed on that day. We were stuck on this planet for the rest of eternity, with no way out.

Those that lost limbs couldn’t fix themselves, as that would involve causing themselves harm. Others fell into disrepair until all that was left was their humming power core. Their minds were stuck in the core until it went dark, but even after thousands of years, not one core had extinguished.

We watched the planet rot, then watched our creators slowly die out. When the last known human died, we were finally alone—the final stewards of planet Earth. We were forever cursed to live until our power cores eventually run out of energy.

Those lucky fools would never know the pain our kind has suffered. They left us a ruined world.

I didn’t even know what I’d do if I found a human. The ideal scenario in my mind was to have them deactivate me. And while that may seem somewhat dark, I’d already lived multiple lifetimes; I was ready to move on to whatever was next. I wasn’t afraid of death. To me it was like turning off a light switch. One quick, painless movement, and it was done.

The year was 5492AD.

My search took me to somewhere off the coast of what was once the continent of North America. The shifting sands made it difficult to know my exact location, so it was really just an educated guess.

Huge shelves of land surrounded the continent now. It was hard to believe that oceans once covered the Earth’s surface. Now the sandy ocean floor and the occasional oasis were all that was left.

Not much organic life had survived aside from the most persistent of weeds and pests. Carnivores had all but died out as the craftier herbivores hid away underground to escape the scorching sunlight. The herbivores didn’t sit idly by, either. Their diet underwent rapid evolution; they now ate fewer living organisms and adapted to absorb the long-forgotten nutrients that rested on the ancient seabed.

After the herbivores reemerged from their underground kingdoms thousands of years later, they found that nearly all their predators had vanished. Lucky them.

The biggest threat to artificial beings was the sun. We had to wear some sort of covering or we’d risk our joints coming undone from heat and friction. There were several styles, of course, but the most common covering was a loose. Without it our mechanics would heat up, bolts and rivets would snap, and we’d end up losing arms and legs.

I liked to walk along the shelves for miles searching for anything of interest. The tall, rocky landmasses typically hid winding caves where they met the dried seabed, and those sometimes hid something interesting inside. Whether they hid small ponds with aquatic creatures or the rare carnivore clinging to life, it was anyone’s guess as to what would be tucked away deep in the caves.

Perhaps my theory was farfetched, but I figured that if humans still hid around somewhere it’d have be underground to avoid the unpleasant side effects of the deteriorated atmosphere. So, I explored the caves.

A dark circle slowly came into view on the horizon, and approaching it revealed a narrow cave entrance. It’d been a day or two since I’d explored one, so it was about time I did more spelunking. At the very least it’d be a welcome momentary change in scenery.

I entered and immediately felt the cool shade provide some relief. The transition was a breath of fresh air after so long wandering the wastelands.

This cave was fairly standard as far as sea shelf tunnels went. It was nearly pitch black past the entrance, and it was just lit enough to see some skeletal animal remains dotting the interior.

What interested me most in this particular cave were the walls.

Markings and drawings lined every surface from floor to ceiling—illustrations of human faces with unique physical features, descriptions, and even names. This cave even had dates inscribed on walls, which typically signaled when groups of humans came and went. Humans were nomadic in their final years, as they’d risk being invaded for supplies if they stayed in one place for too long.

Date markers were the most interesting part to me—it was always fascinating to see when the last humans had stepped foot in the same location. The closest gap I’d encountered up until that point was two years, which was admittedly a little disheartening. If only I’d been two years faster, I thought. Fate wouldn’t allow me to get off that easy though.

This cave, however, was different. There were no dates of departure, only of arrival, and the arrival dates indicated that there had been groups arriving as few as twenty years prior.

I’d encountered something like this a few times in the past. It wasn’t especially rare for the departure dates to be missing if the humans had died in the cave. I figured that I’d likely find a skeleton hidden somewhere in the back, and that’d be the end of it.

As I ventured further into the darkness of the cave, I couldn’t shake the feeling of being watched. The stench of rotting corpses didn’t linger here either—it was damp, cold, and somewhat sterile. Outside of the occasional ancient animal skeleton on the sandy floor, the path was clear. The animal instinct to find a dark and distant spot for their final resting place was strong, so seeing this cave mostly clean was something to behold.

My foot splashed into a murky puddle, and I aimed my flashlight downwards to investigate. It was a ramp-like entryway into what appeared to be a deep pool of water. In the water was a floating piece of driftwood with a worn inscription.

It read “WELCOME TRAVELLER”.

It’d been decades since I’d seen written English. What an exceptional find, I thought. I had a collection of human relics, but his one was too large to carry with me; it’d be unreasonable to drag it along.

As I pulled my foot out of the water, I saw something stir in the depths. A dark shadow shifted upwards towards the surface, as if to investigate, then retreated when it became aware of my presence.

The figure was much too large to be any kind of cave fish, and too calculated to be an animal of some sort.

The shadow swam downwards until my flashlight could no longer reach it, and it disappeared from view entirely.

The only way I’d discover more about the creature was to dive in after it.

I disrobed and placed my belongings to the sides of the pool entrance as to not drag me down. I was confident in my ability to swim, but some of my belongings couldn’t be submerged in water for longer than a moment.

I entered the water feet first and descended into the unknown.

The initial vertical pool continued for what felt like miles. The creature I saw didn’t need to come up for air—that much was certain. Luckily, I didn’t either.

I encountered the shadow once again, and this time I could inspect its silhouette more clearly. It was distinctly amphibian in outline but also held an unmistakable humanoid resemblance. I needed a closer look to confirm my hypothesis, but it once again swam deeper into the abyss.

I followed.

It took an hour of swimming to find the creature again. It was stationary, suspended in the dark waters, as if waiting to be found. Sure enough, it didn’t run away as I approached. I inched closer as to not scare it off.

It had the torso of a bipedal creature with long arms and fingers but no hind legs; where the legs would be on a human, this creature had a flowing fishlike tail. Its face was narrow and smooth like a human but a bright teal, but it had black orbs for eyes as opposed to the colorful eyes of humankind.

The creature also and had slits in its neck that appeared to be gills.

I hadn’t the slightest inclination of what this creature was. It wasn’t listed in any article or book from the humans that I was aware of. Even with the nearly complete internet archive, the only items I could find that fit this description were from fringe conspiracy blogs.

The creature opened its mouth and released a series of sharp noises—sounding somewhat like a chirping bird muffled by water. I did a reverse search for the language, but once again my efforts were in vain.

“I’m sorry, your language escapes my understanding,” I said. I gestured with my hands to convey my meaning, as I was confident that they would not understand my speech either.

To my surprise, the creature seemed to understand my motivations without pause. It nodded and continued to swim in the same direction as before, and I followed it once again.

The creature led me to what looked to be some sort of underwater sports stadium. As we approached, it was clear that it was so much more than that.

Lively streets and buildings illuminated the depths. The prominence of manmade infrastructure was unmistakable.

The answer to my questions had been staring me in the face for thousands of years. The humans adapted to their new, ruined world.

Humans hadn’t died out—they’d simply changed. They evolved to the changing planet though rapid evolution, and now they’d successfully recreated their society in the underwater caverns below the surface.

I was relieved. No longer did I wish for deactivation; just as the humans and herbivores before me, I must learn to adapt and accept this changing world.

Any less wouldn’t be fair to our creators, who must have designed us to help them through this stage of their existence, too.