Did our ancestors build large structures without using modern materials like cement and steel, despite not having scientific knowledge about them?

Well let’s look at the pyramids at Giza, three huge structures all made of hand-crafted stone no cement no steel just hard work, Peru, has its temples of the Incas, again no cement no steel, and they were that perfect a fit you cannot get a piece of paper between the stones, all over the world you will find structures like these that were built with no cement and no steel. then there is Stonehenge in the UK, the blue stone was from Wales hundreds of miles away how did they get it there and how did they stand them up, more to the point WHY did they build it?