Nobody has solved how the great pyramid of Giza was built. The most commonly accepted theory involves ramps. This is pretty much the only way the giant blocks of stone could have been lifted so high in those days. Unfortunately there is zero evidence that the ramps ever existed, and they would’ve used more materials that the pyramid itself.

My preferred theory is prominent enough to be detailed in Wikipedia, but not accepted by mainstream archaeologists. Limestone concrete. The concrete is created nearby, carried in liquid form up the pyramid, and poured into place. If true it is quite an easy way to build the great pyramid, and perhaps every pyramid. There is some evidence: un-natural bubbles of air found in a sample from a pyramid block.

However, in the last 14 years there hasn’t been much talk about the concrete hypothesis. Until now. At another ancient megalithic structure, on the other side of the world, concrete has been proven to be used. The study is very scientific and rigorous. Here are some quotes:

The study carried out on the monumental stones constituting the Pumapunku site in Tiahuanaco, Bolivia, proves that the stones are artificial and are not carved with unknown technology or by extraterrestrials. It is the human genius, intelligently exploiting the resources of its environment, who created these marvels.

…In November 2017, the scientists gathered samples taken in the red sandstone and andesite from the Pumapunku site. For the first time, these stones were analyzed under the electron microscope, this had never been done before! They discovered the artificial nature of the stones.

…this scientific discovery confirms local legends that say, “The stones were made with plant extracts able to soften the stone.”