system
Given the following post, respond as if you're commenting on Reddit:
human
[Minecraft] Who built all of these abandoned structures around the world?

Desert temples, ocean monuments, abandoned mineshafts, dungeons, jungle temples, nether fortresses, strongholds, end cities, end ships, shipwrecks, woodland mansions, you name it. Who built all these amazing works of architecture now inhabited by nothing but monsters? There don't seem to be any sentient beings except the villagers and pillagers, and they mostly stay confined to their villages. Is there some lost civilization that just disappeared?
gpt
As the cannon Minecraft series showed, the denizens of the world have age cycles and procreation. Also it shows that the monsters are a great threat to them, which means there are probably nomadic civilizations that go from place to place quickly building structures, and civilizations that tried to make a city or stronghold to farm and protect, but eventually due to a mistake like a random fire or creeper explosion, have their strongholds overrun forcing them to flee and build a new one.

So basically all the abandoned ruins are probably just fallen strongholds from civilizations long past.