This is /r/AskHistorians, not /r/AskReddit. You don't have to put a [serious] tag on anything. Serious goes without saying. That being said - you're also too vague for our parameters. I'm going to ask you to resubmit the question, being more specific as to what you mean by "ancient civilizations" - Romans? Greeks? Egyptians? Ancient Chinese? Aboriginal Australians? You need to be more specific, either with your area or with your time period, or preferably both.

I'm deleting this, but please resubmit once you've decided on the specifics you're asking about.