Sacsayhuamán – Demons Playground that probably killed 3,000 people

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Sacsayhuaman Monolith

Sacsayhuamán “House of the Sun”, Cusco, Peru is one of the UNESCO World Heritage sites which covers a lot of mystery in it. Undoubtedly piece of masterwork Incas did with stones is remarkable, especially at the altitude of 3,701 m (12,142 ft).

Located on a steep hill that overlooks the city, the fortified complex has a wide view of the valley to the southeast which was capable of accommodating 5000 fighters. Archeological studies of surface collections of pottery at Sacsayhuamán indicate that the earliest occupation of the hilltop dates to about 900 CE.

The longest of the three walls is about 400 meters. They are about 6 meters tall. The estimated volume of stone is over 6,000 cubic meters. Estimates for the weight of the largest andesite block vary from 128 tonnes to almost 200 tonnes.

For comparison, Blue whale weight lies between 50-150 tonnes. So just imagine some group of people lifting 3 whales over the steep hills. 

Can Reverse Calculation Possible?

How many humans were required to perform this mammoth task? Estimates tell us that approximately 20,000 to 30,000 people were needed for the construction of Sacsayhuamán for 60-70 years. Let’s try to get some high-level figures to lift 120 tonnes stone. Try, to find out value by some reverse engineering. How many humans are required? (This is a very high-level calculation to get the idea)

Reverse Calculation for Finding Number of Humans

Energy to lift a 1-ton block up to 0.5 meters. I assume at least the block was lifted up to 0.5 meters = 5 KJ

Energy to lift 120 Tonnes block up to 0.5 meters = 600KJ / [*815 HP] /**1100MP

*735.5J = 1 HP

**Convert HP to Man Power. To support this we can use a fact where a human can generate 0.5 HP for about 15 to 20 minutes if he is an extremely powerful endurance athlete. But we can assume that early humans were more powerful then today then safely we can take 0.75 HP/MP. This data is when we are not considering any other factors like how much distance they planned to cover in one day. 0.75 HP = 1 MP

To handle any accident in between at least 20% buffer in terms of MP we can add (~1300 humans were required to manage one monolith)

If one time 10 different teams lifted 10 blocks, (~13000 humans were required just to handle monolith). Still carving, placing and other activities of stone are yet to add)

Comparison with Today’s Machines

Let’s try this effort with today’s machine. We can compare this calculation with the train engine where the latest train can manage 1 ton in 2.2 HP. So for 120 hp 264 hp where the track is very smooth.

To run on the steep track and full of hills and stone we can safely multiply by 4 times (1056 hp). We get approximate close value to our calculation.

Reverse Calculation for Duration

Let’s try for a number of construction years which is 60-70 years. This area was spread in 3000 hectares. Currently, there are 3 main walls is a remaining average of 400 meters. If we assume an average 1 monolith width is 3 meter then it will be around 133 stones. At least it is a wall of 3 stones one over the other in one wall itself, then there are 400 stones. Currently, there are 3 walls.

So 1200 hundred stones. But if we see a statement from the siege of Cusco, the Spaniards began to use Sacsayhuamán as a source of stones for building Spanish Cuzco; within a few years, they had taken apart and demolished much of the complex. The site was destroyed block by block to build the new Spanish governmental and religious buildings of the colonial city, as well as the houses of the wealthiest Spaniards. In the words of Garcilaso de la Vega (1966:471 [1609: Part 1, Book. Bk. 7, Ch. 29]): [Credit]

“to save themselves the expense, effort and delay with which the Indians worked the stone, they pulled down all the smooth masonry in the walls. There is indeed not a house in the city that has not been made of this stone, or at least the houses built by the Spaniards.”

If we assume there were 10000 monoliths lifted to Sacsayhuaman’s location, it will not be an exaggeration. Let’s try to find a number of years Incas may take to build this location.

10 different teams are lifting 10 huge monoliths and in 10 days, they could reach on top of the mountain. So 1 monolith in 1 day. So  10000 monoliths required 10000 Day   ~27 Years

Here we can see that it takes ~30 years to carry the stones. So it might take 60-70 years to build this fortress where carving and arranging the stone’s effort is also yet to add. We can safely assume that our above calculation is almost correct (All the above calculation is just to calculate the high-level value to re-check the timeline). 


But if this the case then one big query float in my mind.

  • What kind of passage is required to accommodate ~1200 people they could walk together in sync by lifting 120 tonnes of monolithic?
  • How Incas could make this possible without advanced technology, it is a big mystery?
  • What if by mistake one big 120 tonnes monolith slipped through the mountain. One even cannot assume what kind of catastrophe it can create if this mistake happened. 

Mythological Story on Monolith

There is one story which I read in “Graham Hancock – Fingerprints Of The Gods P58” where one such incidence is mentioned.

Garcilaso reported something else interesting. In his Royal Commentaries of the Incas he gave an account of how, in historical times, an Inca king had tried to emulate the achievements of his predecessors who had built Sacsayhuaman. The attempt had involved bringing just one immense boulder from several miles away to add to the existing fortifications: ‘This boulder was hauled across the mountain by more than 20,000 Indians, going up and down very steep hills … At a certain spot, it fell from their hands over a precipice crushing more than 3000 men. The report suggested that they possessed no experience of the techniques involved and that their attempt had ended in disaster.

Although to prove things true fact is required but still we go through some things which our mind will deny to accept. Sacsayhuamán is one such mystery where facts say something but the mind denies the facts. Without demons/giants, this construction could not possible. Most people today, consider the fortress an Inca construction. Though, they themselves told the Spaniards that Sacsayhuamán was built by “giants”.

Amazing Facts about Sacsayhuaman

  • The meaning of Sacsayhuamán is “House of the Sun” 
  • Sacsayhuamán was a massive fortress of the Incas capable of accommodating 5.000 fighters. 
  • Placed at the altitude of 3,701 m (12,142 ft) 
  • The immense fortress was put together with the usage of huge stone blocks. 
  • The city of Cuzco was built in the shape of a puma, a holy animal in the Inca beliefs. The head of the puma was actually Sacsayhuamán. 
  • Specialists affirm that originally, the walls of the fort were approximately 3 m (9.84 ft) higher than today. 
  • It is believed that the entire city below is made by cutting the these stone

I hope you read something new today. Share your views in the comments section below.

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Hello, My name is Dheeraj Jain. I am a software engineer by profession and hobbyist historian. I am trying yo write content that has not been explored in the past. More info about me @

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