Why Are Ancient Ruins Always Buried Underground?

One question  which always bothered me as a kid who was interested in archaeology was why was it that ancient ruins were always found underground? Was the world getting bigger, in some way, that these ruins were being buried by the ever increasing size of the Earth? While you can probably get my youthful logic, this isn’t the case.  One of the main reasons is that cities are simply built on top of each other, with each successive wave of construction simply building on top of the rubble underneath (for the sake of expedience – clearing is hugely expensive and time-consuming).   So, if a building was rebuilt, it meant that it would be higher than the surrounding streets.  The obvious solution there was to raise the streets too.  That means that in some places, buildings are 18 meters higher than they were in the 1^st Century AD.

When it comes to archaeology, building one layer on top of another isn’t the only reason why so much archaeology lies underground. The cities of Shanghai and Seattle, for example, are gently sinking into the ground because of the weight of the buildings on top, not to mention the extraction of drinking water from below. 

Still a little discombobulated by it all? Then watch this video from Primal Space, which explains it very clearly and with great computer-generated animations to match.

But this still leaves another puzzle: what about places like Roman villas, farmsteads or temples that weren’t built over by later generations, but simply abandoned? Why are they buried too? The answer is that ruins often begin by burying themselves. Roofs collapse, walls tumble, plaster crumbles and timber rots away, creating a mound of debris. Over the centuries, wind-blown dust, flood silt, leaf mould and soil gradually build up around and over the remains, while roots, weather and farming slowly break them down further. In other words, even when nobody builds on top of them, time and nature usually do the job anyway.