I spent some time in an Italian hill town that has been continuously inhabited since the Romans. At the same time I visited Pompeii. Most of the buildings in the center were Roman and had identical construction to Pompeii. They were living "ruins" and therefore could not be discovered because they had never been lost. There was a Roman Theater in that town that had been partially built into homes and partially quarried for building materials. There had been a set of giant marble masks originally in the theater, but now scattered around the town built into other building. Conservation of matter, it doesn't go anywhere unless someone carries it away.

Say you lay a road in a town, then the road starts developing holes; to even it out, you place a new layer on top. Over decades, this process raises the road so significantly that, when buildings are demolished, they get rebuilt at a higher level or their ruins are simply covered by new roads. Rinse and repeat for centuries, and you end up with Rome.

If instead you just abandon the settlement (like it happened in many Egyptian / Greek / Roman towns, like Volubilis in Morocco), then nature will do its thing, pushing detritus over the ruins, or growing plants that will slowly create new layers of organic material that eventually turns to dirt. Towns near rivers or coasts might be claimed by waters once people stop maintaining their protection. Etc etc.

I think post has what you need.

Now it is believed that the city was the capital of some (Assyrian?) kingdom, that just 200 years earlier was basically the capital of the civilised world and had stood for hundreds of years. It was destroyed by a particularly cruel horde, and everyone in it was slaughtered, the fields around it salted, the goods and artefacts taken.

It was so thoroughly destroyed that 200 years later a well read and knowledgable general couldn't even place it or find anyone to tell him about it. The only thing that remains were the basically indestructible stone walls.

I don't really have the mind for remembering history details, so I'm probably way off on some details, but I thought it was a cool story about how we've come to find these ancient ruins just all abandoned without even locals knowing what they are. Dan Carlin makes it really come alive, highly recommend listening to his stories.

“Why Ancient Rome Is Buried”: https://youtu.be/fz4ZdXpri04