Snake melted in stone Peru. It certainly seems to me some Type of heating method was used to penetrate the stone. Hopefully someday we will find the answer. Blows one's mind to think of ancient men having such skill.
Puma Punku in Tiahuanaco - Never underestimate how big these stones are. some are estimated to weigh 1000 tonnes and so precisely placed. Not to mention the interlocking and impossibly machined angles. Check it out!