At the northern end of the Sacred Valley, Ollantaytambo is rare if not unique in Peru. Ollantaytambo is a massive citadel located 50 kilometers from Machu Picchu. The citadel served as both a temple and a fortress. At some time unknown, and for reasons unknown, work mysteriously stopped on this huge project.

Inca terraces (left) and megalithic wall (right) at pre-Inca site of Ollantaytambo.

Mysterious Pre-Inca megalithic stonework at Ollantaytambo

Stone Technology

The Sun Temple (above) that was constructed with huge red porphyry (pink granite) boulders. The stone quarry is named Kachiqhata (Salt Slope) and is located about 4 km (2.5 miles) away on the other side of the valley, by the upper side of the opposite south-western mountains. The boulders were carved partially in the quarries, and taken down to the valley’s bottom. In order to cross the river Quechuas constructed an artificial channel parallel to the natural river bed that served for deviating the river’s water according to conveniences. Therefore, while that water flowed through one channel the other was dry, thus stones could be taken to the other side of the valley. More over, the boulders were transported to the upper spot where the temple is erected using the inclined plane that is something like a road which silhouette is clearly seen from the valley’s bottom. They had the help of log rollers or rolling stones as wheels, South-American cameloids’ leather ropes, levers, pulleys, and the power of hundreds and even thousands of men. Today, on the way from the quarry to the temple there are dozens of enormous stones that people know as " tired stones" because it is believed that they could never be transported to their destination; those stones are the reason why some authors claim that the Sun Temple was unfinished when the Spanish invasion happened.

Massive, multi-sided blocks were precisely fitted together in interlocking
patterns in order to withstand the disastrous effects of earth quakes.

Scientists speculate that the masonry process might have worked like this: after carving the desired shape out of the first boulder and fitting it in place, the masons would somehow suspend the second boulder on scaffolding next to the first one. They would then have to trace out a pattern on the second boulder in order to plan the appropriate jigsaw shape that would fit the two together. In order to make a precise copy of the first boulder’s edges, the masons might have used a straight stick with a hanging plum-bob to trace its edges and mark off exact points for carving on the second boulder. After tracing out the pattern, they would sculpt the stone into shape, pounding it with hand-sized stones to get the general shape before using finger-size stones for precision sanding. Admittedly, this entire technique is merely scientific speculation. The method might have worked in practice but that doesn’t mean this is how the ancient Quechua stonemasons did it.

"How were such titanic blocks of stone brought to the top of the mountain from the quarries many miles away? How were they cut and fitted? How were they raised and put in place? Now one knows, no one can even guess. There are archaeologists, scientists, who would have us believe that the dense, hard andesite rock was cut, surfaced and faced by means of stone or bronze tools. Such an explanation is so utterly preposterous that it is not even worthy of serious consideration. No one ever has found anywhere any stone tool or implement that would cut or chip the andesite, and no bronze ever made will make any impression upon it."

A. Hyatt & Ruth Verrill —-America’s Ancient Civilizations

Jean-Pierre Protzen thinks the Verrills was wrong. He went to Cuzco and showed how river rocks could be used as hammers to pound stones into the desired shape.

"It appears that the Inca technique of fitting the blocks together was based largely on trial and error. It is a laborious method, particularly if one considers the size of some of the huge stones at Sacsahuaman or Ollantaytambo. What should be kept in mind, however, is that time and labour power were probably of little concern to the Incas, who did not have a European notion of time and had plenty of tribute labour from conquered peoples at their disposal."

Jean-Pierre Protzen —Scientific American —Feb. 1986

Was this monolith carved with stone tools?

Eric Von Daniken, in his series of books beginning with Chariots of the Gods theorized that the Andean stone-works were build by Alien/Gods who visited the earth long ago, bringing civilization to primitive man. The scientific community simply snickered.
Whatever one thinks of his theories, he brought to the public an awareness of the many ancient monuments on earth that seem to defy rational explanation.

Everybody who has traveled to Egypt, Mesopotamia, South America and many ancient places has seen it: the astonishing craftsmanship of these ancient stoneworkers. The precision fit of large stone blocks is eminent in both the Old and New World. It is hardly imaginable, that all of this should have been done by pure manual work alone. This very interesting link, Ancient Stone Technology, also includes theories of Professor Davidovits from the Geopolymer Institute in France.
In short, his theory is that the 2 million blocks of limestone that make up the core of the pyramid of Chufu (Cheops), have not been cut into shape, but the limestone was solved in water, brought to the building place in small portions and then the blocks were cast in situ. Even more interesting are his ideas on the precision-fit Inca walls: He puts forward a technique to soften the stone by use of acid plant extracts!