As the sibling comment says, cities are not buried - they are subsumed by material that accretes on top of existing structures. Say you lay a road in a town, t

As the sibling comment says, cities are not buried - they are subsumed by material that accretes on top of existing structures. 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.