There are huge amounts of proof of an ancient worldwide civilisation (probably giants) that built the megalithic structures. They were defiantly very intelligent, highly technological, artistic, had heavy lifting gear and power tools.
This video shows a way of drilling holes in stone using sound, a steel sphere and a copper pipe.
Of course this would mean that the ancients first had to be capable of making a steel sphere and a copper pipe. They'd also need some way of producing the sound wave forms and some sort of sound amplification system (maybe electronics). I'm quite sure the people that lived over 12500 years ago, before the end of the last ice age (and the flood), could do all of these things but I think they'd probably just use some sort of hand held hammer drill instead.