How do we know it took 20 years to build the pyramids?

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The pyramids of Egypt are among the most impressive structures ever built by humans. These colossal structures have fascinated scholars and historians for centuries. One of the most intriguing questions about the pyramids is how long they took to build. The traditional answer is that the Great Pyramid of Giza, the largest of the three pyramids, took 20 years to construct. But how do we know this?

How do we know it took 20 years to build the pyramids?

The 20-year timeframe is not based on any single piece of evidence. Rather, it is the result of a synthesis of various sources of information, including ancient texts, archaeological evidence, and modern scholarship. In this blog post, we will explore the different lines of evidence that support the 20-year timeline for the construction of the pyramids.

The Ancient Egyptian Texts

The ancient Egyptians left behind a wealth of texts that provide insights into their society and culture. One of the most important texts related to the pyramids is the “Palermo Stone,” an ancient document that dates back to the fifth dynasty of the Old Kingdom (around 2400 BCE). The Palermo Stone is a collection of annals and records that chronicle the reigns of various kings and pharaohs. Among the events recorded in the Palermo Stone are the building of the pyramids.

According to the Palermo Stone, the construction of the Great Pyramid of Giza began during the reign of Khufu, the second pharaoh of the fourth dynasty. The document records that the construction took 23 years, which is close to the traditional 20-year timeframe. However, the Palermo Stone does not provide any details about the construction process itself.

The Pyramid Texts, another important ancient Egyptian text, provide some additional clues about the construction of the pyramids. The Pyramid Texts are a collection of religious texts that were inscribed on the walls of the pyramids during the Old Kingdom period. Although the Pyramid Texts do not provide a direct account of the construction process, they do contain references to the labor involved in building the pyramids. For example, some of the texts describe the role of the pharaoh in overseeing the construction and directing the laborers. Other texts mention the use of ramps, sledges, and other tools that would have been necessary to move the massive blocks of stone used in the construction.

Archaeological Evidence

In addition to the ancient texts, archaeologists have uncovered a wealth of physical evidence related to the construction of the pyramids. One of the most important pieces of evidence is the workers’ village near the pyramid complex at Giza. This village was home to the laborers who built the pyramids and was equipped with everything they needed to live and work, including bakeries, breweries, and a hospital.

Excavations at the village have revealed that it was occupied for a period of around 20 years, which supports the traditional 20-year timeline for the construction of the pyramids. In addition, archaeologists have found evidence of the tools and techniques used in the construction process, including ramps and sledges. They have also discovered quarries where the stone blocks were extracted and workshops where they were shaped and polished.

Modern Scholarship

Finally, modern scholarship has played an important role in shaping our understanding of how long it took to build the pyramids. Scholars have conducted detailed studies of the construction process, including the logistics of moving the massive stone blocks and the organization of the labor force.

One of the most influential modern studies of the pyramids was conducted by French architect Jean-Pierre Houdin. Houdin developed a detailed theory of how the pyramids were built, which he called the “internal ramp theory.” According to this theory, the construction of the Great Pyramid of Giza was accomplished using an internal ramp that spiraled up through the pyramid as the building progressed. Houdin’s theory has been widely accepted by scholars and provides a detailed explanation of how the construction could have been completed in 20 years.


In conclusion, the 20-year timeline for the construction of the pyramids is supported by a variety of sources, including ancient texts, archaeological evidence, and modern scholarship. While there is still much that we do not know about the construction process, the evidence that we have suggests that the pyramids were built over a period of two decades by a massive workforce using sophisticated tools and techniques. The pyramids remain a testament to the ingenuity and skill of the ancient Egyptians and continue to inspire awe and wonder in people around the world.

How do we know it took 20 years to build the pyramids?
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