The megalithic stone walls of Saksaywaman

Unravelling the mystery behind the megalithic stone walls of Saksaywaman

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Lying on the northern outskirts of the city of Cusco in Peru, lies the walled complex of Saksaywaman (Sacsayhuaman). The site is famed for its remarkable large dry stone walls with boulders carefully cut to fit together tightly without mortar.  The stones used in the construction of the terraces at Saksaywaman, which weigh up to 200 tonnes, are among the largest used in any building in prehispanic America, and display a precision of fitting that is unmatched in the Americas. The stones are so closely spaced that a single piece of paper will not fit between many of the stones. This precision, combined with the rounded corners of the blocks, the variety of their interlocking shapes, and the way the walls lean inward have puzzled scientists for decades. 

The magnificent interlocking stones at Saksaywaman

The magnificent interlocking stones at Saksaywaman. Photo source: Hakan Svensson

The method used to match precisely the shape of a stone with the adjacent stones has been the focus of much speculation and debate. Various theories put forward include: stone softening using a mysterious liquid derived from a plant, mineral disaggregation from the heat generated from large sun mirrors, and even extra-terrestrial intervention. However, John McCauley, retired Architect and Construction Manager, who has been engaged in research on ancient construction techniques for over 40 years, has a different hypothesis, and it lies simply in the ingenuity and wisdom of ancient people.

“We have to remind ourselves that the steady rise in mankind’s mastery of technology has taken place over thousands of years of trial and error; mastery of a successful technique in moving heavy stones, or in carving them, has only occurred because of the knowledge passed on through the failure and success of countless ancient engineers who were willing to experiment with a new thought, and have at their disposal a seemingly endless field of labor to execute their ideas,” wrote Mr McCauley, in a paper submitted to Ancient-Origins.

Mr McCauley has carried out an extensive investigation of the Saksaywaman site in Peru, reviewing many possible methods for transporting the 25-200 tonne stones and has concluded that the lighter stones were dragged over carefully prepared natural soil beds, while the heavier stones were transported on timber sleds. Model testing on various roadbed constructions resulted in the estimation that the heaviest stones could have been moved by no more than 1,000 men.

Once at the site, Mr McCauley says the stones were shaped using very heavy “pounders” and countless hours of labour to create the magnificent megalithic walls that can still be seen to this day.  Each blow of a diorite boulder, he explained, would remove a small amount of stone until the final shape was attained, “This would take days and weeks, if not months of toil depending on how much material had to be removed.”  He explained that another technique, called “trial and error”, was used with much lighter stones. With this method, the stones were shaped with pounders and, as the work progressed, “one stone was mated with another stone until the two finally fitted well”.

The following sequence of photos, using scale models, and descriptions have been provided by Mr McCauley to illustrate how the ancient Inca may have been able to very accurately transfer the shape of stones in the megalithic walls. 

Model Photo 1

Saksaywaman Stones - Model Photo 1

“In this sequence, the assumption is made that an opening has been made in the wall and it needs to be filled with another stone. A wooden board is secured in the opening and spanned to two sides of the opening. A scribe is moved along the edge of the existing stone edge always holding it at the exact same angle to the angle of the wood so as to copy the shape of the stone very precisely                                                                                          

The individual wooden template is then removed from the void space in the wall and is shaped with bronze tools and flint scrapers, resulting in a shape that is true to the edge of the void. The same sequence is performed for each edge of the void space. Each template board is tested against the shape that it copied to verify accuracy.”

Model Photo 2

Saksaywaman Stones - Model Photo 2

“The master template for the entire void shape is then assembled with wooden dowels and inserted into the existing void space in the wall to verify that it fits exactly. The pinned and doweled joints are verified to be tight.”

Model Photo 3

Saksaywaman Stones - Model Photo 3

“Now the hard part! The completed wood template is placed over a stone in the marshalling yard which most closely represents the shape needed in the void in the wall. These stones are laying in the stone marshalling yard in front of the wall which is being built. The master template is secured in place with stakes and ropes. The stone masons then transfer the shape of the template to the face of the stone. This transfer of the shape has to be done very accurately and is accomplished by using a narrow scribe board held firmly against the side of the template. This narrow scribe is used to mark the stone so that it can be cut precisely the same shape as the template. The stone masons then remove the template and begin to shape the stone based on the lines that were transferred from the wood template. After the rough carving has been completed, the template is used again to measure the accuracy of the shaping.”


They must have imported the wood for the sleds and templates. I have an idea too...they were more techonologically advanced than archeologists give them credit for, If you look in the surrounding areas there is evidence of machine tooling. Hey guess what, we always assume that we know more than people did in the past.

There is an abundance of forests near Cusco, Peru, where Sacsayhuaman is located.

i am an old who thinks a lot, because i don`t have the energy to do much else.
what about placeing a suitable stone on a stone underneath it and one to the side of it
and slide it backwards and forwards a few inches and i think it would eventually fit perfectly,
if this was done from say left to right there would be no need to fit stones into three sided gaps.
sorry if i wasted your time , it was just a thought , tom

I think you are right on the money. I can see this in the presentation and have always figured this as a very viable method because you can indeed see what appears to be a sequence of fitting each new Block into both a Vertical and Horizontal Stone simultaneously  I think the source quarry may have blocks already “fractured” to block shapes similar to Basalt. They then picked the “Best fit”...rough shaped each Stone...then slid it back and forth on an aggregate “Mud" of water and sand or even the “Grindings" from the two Stones themselves until the Stones conformed each other to fit. Now how they moved Stones of this size back and forth is another matter. I would be very curious if the Stones in the the source Quarry are indeed fractured and naturally come out block shaped. Taking avantage of natural circumstances like this have always and are still being practiced even today, Slate and Flagstone are prime examples of this. Just look at the Ancient Pueblos that were built with naturally shaped blocks of Flagstone. I think you are on the money with the sliding back and forth one block at a time until they conformed to each other as the final fitting. I have thought this since the very first picture of these I saw as a child, you can almost number each Stone in order as the next one fitted into place. I think what happens is we do not have the patience that the Ancients had and are looking for a “Quick” way to accomplish these things rather than understanding they were in no hurry and didn’t mind the time it takes to do things like this one block at a time.

Long lifes up to 900 years, giantism, big animals, degeneration of mankind, imagine 50 giants and some dinosaurs playing with a 300 ton rock, would be interesting to know what a giant could pull or lift vs the strong men of our time

Guess they had a wood mill, too, to get the boards to make the templates. Trial and error? That makes me laugh. Where are all the ones that didn't fit?

There are 3 methods of fitting stones together in construction:1. "trial and error" where, if a fit doesn't work, you remove the stone and rework it: 2. scribing: and 3, templating. Trial and error only works with very small stones. There was no need for a "mill". As we see in ancient Egypt and Peru, Mexico, and Bolivia, the ancients were very capable of cutting wood, assembling timber structures and cutting wood with copper, bronze or flint tools. In order to demonstrate this technique, smooth boards were used in the model.

There are 3 methods of fitting stones together in construction:1. "trial and error" where, if a fit doesn't work, you remove the stone and rework it: 2. scribing: and 3, templating. Trial and error only works with very small stones. There was no need for a "mill". As we see in ancient Egypt and Peru, Mexico, and Bolivia, the ancients were very capable of cutting wood, assembling timber structures and cutting wood with copper, bronze or flint tools. In order to demonstrate this technique, smooth boards were used in the model.

Mystery not unravelled by this theory..

It is very difficult to summarize 10-years of study and 200-pages of research on this subject in 3-pages of an essay. I can testify to the fact that I have reviewed every possibly method of moving large stones and carving them with various experts around the world.

If there was a way of publishing the 200-page research paper I performed over 10-years, you might be convinced!

As described, this accounts for only two dimensions. From doing similar work, I can assure you that's not good enough, unless I'm misunderstanding something.
Which I have also done in the past. ;)
In any event, thank you for an interesting site.

The stones at Sacsayhuaman have joints that fit very well "up front". Once you uncover the joints towards the rear, the two stones do not touch each other. Therefore, it is not necessary to create a 3-D replication of the fit between stones. Only the "seat" between two stones is fitted throughout.

Many of the stones have long grinding strips or scrapes that are linear. These do not fit the pounding model. Simila marks have been found in Egypt and even at Stonehenge.

As far as the rear of the stones we use a similar technique today in ladscaping the back of the stones are not fitted as they grip the surrounding soil better.

The so-called "grinding strips" are actually "shallow channels" that were cut into the face of the stone using 5#-20# hard stone "pounders> These channels are evidenced on many of the stones at Sacsayhuaman. A good illustration of this technique is also seen at the tip of the "unfinished obelisk" at Aswan, Egypt.

The strips are inconsistent with pounding stones. There is allways the linear assumption that the pounding stones are contemporary with the structures as well. There are three distinct types of construction in the area to assume they are all done at the same time makes is nonsensical.
I have rad the papers on the subject. They state that this May have been how they were done. They also admit that they cannot be certain. That was archeologist statements. If you have a machinist or stone mason look they will have a slightly different opinion.

Sorry about the typos iPads sometimes have a mind of their own

Absolutely NOT true! It is actually not proper to call them "strips". If you look very closely at the tip of the unfinished obelisk at Aswan, Egypt, for instance, all of these carved channels are parallel. The same is true for the stones at Sacsayhuaman. By pounding the stones in a lineal channel fashion, it is possible to judge the depth to which you cut, rather than a random pattern. The high points between channels was then later removed.

Sorry, but those are marks consistent with grinding, or scraping not pounding. Again it depends upon which style of megalithic structure you are looking at. Hunan Pacha, machine tools. I think that is becoming generally accepted. There are simply too many examples. There are also signs of vitrification at various locations. Assuming they were all done at the same time and by primitives and with the same techniques is again nonsensical. GIve the acients some credit. They did some things we can only guess at.

Sorry, but grinding was not involved at all! Look closely at all the samples. It was simply done with "pounders". There is also NO evidence of "machine tools" in spite of what some would like to believe.
Even looking at the remarkable stones at the Corichancha, the superbly cut and shaped stones can all be explained with tubular drilling, quartz sand cutting agent, and countless hours of rubbing with sandstone, etc.

I am so sorry that you appear generally ignorant of the facts and ca not compose a logical question. So, I am not able to respond in any kind of a sensible manner!

Reading that article logic dictates that (A) it took hundreds of years using the methods described. (B) The world is littered with failures and remnants created as the technology developed over thousands of years to the point where we can no longer replicated it, nor do we even know what that technology was. Duhhhhh!. Finally, if we study the demographics from ancient to modern times we have to ask the inescapable and most obvious question, where did they get all the people from.

Ok, *that's* what I was missing. Thank you for the clarification, Mr. McCauley.
Have a good day.

I'm not disagreeing with this hypothesis, but it doesn't feel right. Organizing a working crew of thousands that are working in sync with shaping these component areas of wall by using individually cut pieces of wood PER STONE or at least, every other stone would be insane. If they were going to have to cut individual stones anyway, why not just make one set of sizing molds and cut each stone to a standard? They were obviously intelligent enough to figure that much out, so it seems to me that there must have been an ease to this that is being missed.

That is simple. If they were to make say each block at one tonne and a certain measurement, then there would be much more work involved at the quarry or from each stone they pick from. Inability at moving large stones was not a deciding factor. They use them in around about the shape they are then tailor another to suit it. Obviously this is why they are also not all level for each course. Which happens to help tie it in. Most cases the largest of large stones are on bottom. Saves lifting them to top. This is correct that pounding was used. Its obvious at the obelisk site. Though there could be something in the plant that produces a liquid that softens rock to make it easier. People suggest the entire rock would be like wet cement but that's not true either.

Tsurugi's picture

Very intriguing. It is good to see real efforts being made toward attempting to truly explain such constructions. At the very least, this idea has some real meat to it, unlike the vague generalities we usually hear, "Well they quarried the stone, moved it here, and built the wall!"


I have some questions though, if that is ok....does this theory follow the idea that the Inca were responsible for these constructions? Does this theory address any of the other myriad examples of anomlaous masonry seen throughout Peru? 


[Edit: Replaced huge hi-res images with versions in a more manageable size]

What is going on here:




...or here:







What about Ollantaytambo? Same builders and techniques, or no? Some features in and around Ollantaytambo would seem rather difficult to acheive using the scraping technique, I think....such as these:

(Note: wall in background, IMO, is Inca. The work in the foreground is not)




Then there's stuff like this:


...and this, so seemingly haphazard, yet obviously of highly sophisticated and superior craftsmanship:


(Note: Upper left, Inca. The rest....somebody else.)



If your idea is only focused on Sacsayhuaman, I apologize. But there are so many interesting masonry sites in Peru, heh. Perhaps they can be explained in isolation....but perhaps not. In any case, I'd like to hear your take on them. 


This topic have been discussed Before in this forum, but I think it fits well into this discussion as well. There are many different myths about how sound made stone fall apart. Also many ancient Buildings have certan harmonic frequencies, that would thenhave to be shared by repeated elements of the construction. Yet again, many of these building or structures are made of homogenous granite.

All those parameters above give one possibility at hand, that sound was used when shaping these stones. A homogenous granite would have a limited size distribution of the different crystals that it is made up of. This would mean that there would be three different harmonic frequenses, one each fitting each type of crystal. These Crystals would adsorb the sound of their harmonic frequency and start to vibrate at a greater and greater amplitude until they would break.

Also a full size stone as a whole,whould have such a harmonic frequency, and if a number of stones would be the same shape and size, they would have the same such frequency. This would also imply that it would be possible to crack a full size stone at a given cross section with suffcient energy input at the critical frequency.

Looking at the structures in Peru, I would imagine the possibility of the final finishing being done using sound to grind the stone surfaces together into this close and even contact.

I think we have forgotten what the ancients knew,and try to explain it away with some nonsense when it is so simple. Knowledge we have forgotten.

exactly! why go the full 'anal' to have them fit perfectly, while 'pretty good' would have been hard enough to achieve with the known technology

Definitely an extremely idiotic theory. If i lived in that era, why go to all the trouble of shaping the stones? Why don't they just pile the stones atop one another finding the "best" fit. As it is, they'll expend a lot of manhours just transporting the stones and piling it atop one another. Hey! I have crops and farm animals to tend to, you know!

A very interesting theory! I can probably add that in those days, food is falling from the heavens, there are a lot of free condos to live in, why, free sex too! People really can't do anything to while their time away, so they cut timber, haul big stones-- the bigger the better, make templates out of the wood as pattern so they can pound the stones to shape, unmindful of the days, weeks or months coz there is nothing to do more worthwhile, anyways. I just can't figure out the purpose of those structures btw, except maybe to mock us, that compared to us, they are having a good time, in their time, and maybe to help some geniuses sell books, by figuring out how they build the said structures. Neat!

Problem here is that they had plenty of time and would have had large enough populations. We seem to have time to work up to 12 hours a day on large bridges etc etc today, even though food wont fall to us from heaven. If we weren't busy building towns, cities and other places to habit. Which is exactly what these places were.There are countless old buildings still standing that took much longer than throwing up some tree posts and thatching a roof. Today farmers can provide for more than one family, just as back then food could be fed to all workers.

In Percy Fawcett's explorations of S. America he came across stories of a plant whose juice would soften rock. In one story a group of explorers found a bottle in the cave and were going to drink it when it fell and broke on a stone. When they looked later they saw the stone appeared melted. In another story someone running through the jungle noticed that after he passed through a space filled with red leaved plants his spurs were worn almost completely away. There were also observations that bird would find these leaves then take them to peck against a cliff in order to make themselves a space for a nest. If this plant did exist at one point it would explain a lot of construction mysteries. The scraping marks we see would make more sense as they would be scraping away soft rock.

This seems more plausible to me than legions of craftsmen pounding away on giant blocks for decades. Regarding that, imagine the cost/benefit ratio when one factors in man-hours, resources (including providing for the workers), and the consequences of thousands of the best engineers and masons around diverting years of their life away from anything practical. Not to mention that same absurd scale of effort could be put toward building less handsome walls like a thousand feet high.

I think McCauley makes more assumptions than he realizes—that progress is linear, that we have full knowledge of the tools available, that said tools are primitive, and that it must follow that what they accomplished with little but time we could accomplish with relative ease today.  And that the ancients were essentially a bunch of highly skilled idiots.

there is some credit to be given to the plant sap melting stone theory, because the chance of a perfect rock splitting in the wrong place, would be too great a risk. There are examples of this melting method used in sisian, southern Armenia. Mega sized stones were placed, stones that have holes "bored" into them t angles, to line up with obscure star clusters & so on. To me, I think they were melted on the griund, then the rocks were lifted into position, using earten ramps and/or timber frames.

Yes, I think we have forgotten more of our past skills as humans, than we could ever learn now. Our problem is once we learn a new way of doing things, the old way is forgotten quickly. Even though it may have been easier, cheaper or quicker in the long run.

For example, look at todays houses, boxes thrown up in a mtter of a month or 2. Whereas in the older days, rooms were never 100% square, had real depth, a sound structure, but took 4-6 months to build, even longer. Ask any estate agent what would they choose to live in, were money no object...

John McCauley is probably on the right track for the preliminary creation of building stones but there may be more to the story in terms of the “perfect” fit of the stones. There are videos on YouTube that show how to use a Fresnel lens to “melt” rock. These spot lens can generate heat up to 3,200k, more than sufficient to create “lava” or obsidian. It takes a few minutes to completely melt the rock but this would not be needed for wall construction.

Various forms of stone crystals were probably known and available to these meso-american people. Note that crystals are used in the construction of some Fresnel lens. Perhaps the ancients learned that some fairly large crystals could be used to soften (not melt) their walls when they were roughly shaped, per McCauley's conjectures. It is possible that some group found a fairly large Fresnel type crystal and introduced this type of softening technology. Later, others picked up the technique and sought additional “usable” crystals.

Consider also the anchoring indentations. Something must have been used to create enough heat to melt the metal poured into these locking devices. Here too a crystal stone similar to a spot Fresnel lens could be used. These “clamps” would not have been of much use in earthquakes, given the size of the stones. As indicated on the “Ancient Mysteries” site ( ) it is more likely these clamps were used to keep a set of stones in place as they settled following the heating process.

Just a few thoughts for your consideration John. Your work is interesting.

Question: Has every instance thus far been proven to be individual stones or are any portion of the stones possibly carved in relief from larger stones?

Lets look at this through a design thought process of the architect or engineer who built this.

From a construction planning point of view the wall was made haphazardly and on the fly without prior planning. We can say this by looking in the extremely irregular shapes and differences of the sizes of stones. The way the article shows how the templating of the stones are carefully and meticulously planned before cutting do not match the design thinking process of making the wall.
If the Killke people were organized and wise enough to build these layered fortifications for defense, why was there less (or even a lack of) organization and planning in the building and design of the walls? Because it was easy for the builders. And no planning was necessary.

We can assume by points here that the making of the wall was not difficult for the builders:

1) The size or the weight of the rocks didnt seem to matter. There was no need to cut the rocks to smaller more manageable sizes, also given the fact that the area was mountainous.

We can hypothesize two things here: The Killke did not build the walls. The workload would be disproportionate to any combined human manpower past or present. The disorganization shows that there were no need of planning needed to ease any difficulty. The precision of the cuts do not match or level to any technology past or present.

2) No planning was needed to fit the rocks in an orderly way (like a regular brick wall for example). The stones, in whatever size was available, was cut and shaped as needed and fitted one by one, working centrifugal to each stone as they were laid.

3) There is a striking contrast in the precision of cutting the rocks and the haphazard random fitting of rocks. If the unorganized design of the rock fittings mean it was easy for them to not need an organized plan beforehand, we can then ask the question 'Why was the cutting so precise and clean given they were doing a 'rough' job on the rock fittings?' These two working processes contrast. This can only mean one thing: Cutting the stones to their puzzle part shapes was not difficult for the builder. Otherwise we should see the cuts as rough and disorganized as the design.

4) The final stone jutting edges that run along the meeting points were smoothed out. The faces of the rocks were also smoothed but the depressed lines of the carving tool used can still be seen on the surfaces. The presence of this marks also seem to indicate the project was no big deal to be given a polished clean finish. So the carving marks were left, like a 'fast and rough' work of someone in a hurry to meet a deadline. Rough, but complete.

5) If dorite stones were used to grind the stones to finish. This would take an enormous amount of time to accomplish. And that would make the wall important to them and the final work should have no rough workmanships marks. Otherwise it is a conflict on build thought process. But it is present, so we can assume that the process used was not time consuming and it was easy, making the wall unimportant, thus the presence of rough marks. Therefore the difficult process of dorite stone grinding is a far fetched idea.

These 5 points show that a careful planning or polishing design thought process was not present. Therefore the theory of careful templating is against and counter to the character of the builders way of thinking.

I wonder if the rocks were already shaped. There are some nice google images of basalt pillows that look at lot like the walls. Maybe they just arranged them more or less in the same pattern that occurred naturally. Sorry for butting in.

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