Precision and power

There is an ongoing debate over what happened in prehistoric times.
Was there an advanced earth spanning civilization in existence prior to some kind of calamity that allegedly happened 12-13,000 years ago?

That got wiped off the face of the earth, leaving only very sophisticated megalithic stone works as evidence of its existence.

Or, as mainstream historians claim, the sudden change in climatic conditions that took place some 12-13,000 years ago spurred humanity on to develop agriculture, rather than hunting and gathering because of a drastic reduction in available game?

If you closely examine the megalithic stone work in walls erected in the distant past, you are struck by the incredible precision used in fitting these stones together so as to make walls very resistant to major earthquakes.

That in contrast to more recent stone constructs using the old walls as a stable base.

The sheer size of the stones also dwarf more recently placed ones.
There seems to be an order of magnitude difference in both the precision and power used to create ancient, as compared to more contemporary stoneworks.

Looking at contemporary society, we can place a rover on Mars and observe what happens on the surface on that red planet on a daily basis because of the precision and power of our technology.

But the stoneworks we would leave behind if some kind of calamity was to happen would likely be mostly rubble in the form of decomposed concrete and major highway earthworks here and there.

So, I think we can say that if there was an ancient advanced civilization, it was very different from our present one.

Maybe they were giants? (Look at the size of the rooms in the ancient city of Petra : )