Actually, Peace, I have to disagree.

Could we build a pyramid in the Central American jungle without our power equipment? Carve and raise the heads on Easter Island? Create a base 12 mathematics system from scratch, much less one in base 16? Create buildings as astronomically precise as Stonehenge, Woodhenge, and tombs of the Boyne Valley? Create and sail craft to populate Oceania? Create a culture that not only survives, but flourishes, in the Arctic?

Our ancestors were quite as sophisticated and knowledgable as we are. True, their knowledge was in different directions than ours, but it was still as dazzling as our own -- and in some ways perhaps more so.