© Getty Images

The Giza pyramids -

The Giza pyramid complex represents perhaps the greatest feat of civil engineering undertaken in the ancient world.

© Getty Images

Giza pyramid complex -

Constructed during the Fourth Dynasty of the Old Kingdom of ancient Egypt, between c. 2600–c. 2500 BCE, the pyramids were royal tombs built for three different pharaohs: Khufu, Khafre, and Menkaure.

© Shutterstock

Khufu -

Khufu was the second pharaoh of the Fourth Dynasty of Egypt, on whose orders the Great Pyramid of Giza was built.

© Getty Images

Khafre -

Khafre, the son of Khufu, was responsible for the building of the middle of the three ancient structures, the second tallest and second largest of the group.

© Getty Images

Menkaure -

Khafre's son Menkaure, seen here between the goddesses Hathor and Bat, was responsible for the construction of the smallest of the main three pyramids at Giza.

© Getty Images

The pyramid field -

The pyramid field also includes several temples, cemeteries, the remains of a workers' village, and the other iconic monument set within the complex, the Great Sphinx of Giza.

© Shutterstock

The building of pyramids -

The construction of these colossal structures, all of which served as tombs for the three previously mentioned pharaohs, each took on average 20 to 30 years to complete.

© NL Beeld

A workforce of thousands -

But the exact methods used to build the most impressive man-made structures in history are still unclear. What is known is that it took anything up to 30,000 people to put them together.

© Public Domain

Skilled laborers -

Contrary to popular belief, the labor force rather than made up of slaves instead consisted of skilled Egyptian workers.

© Getty Images

Highly organized -

Theirs was a highly organized community, rich with resources and likely backed by a powerful central authority.

© Getty Images

Raw materials -

There's no doubt that the work involved was intensive and difficult. It's believed around 2.3 million individual blocks of stone were used to create the pyramids.

© Getty Images

Backbreaking work -

Each had to be pushed, pulled, and dragged into place, no easy task when the average weight of these building blocks was 2.5 tons.

© Getty Images

Worked to death -

Not surprisingly, injuries were commonplace. Many workers were condemned to an early death, killed or injured by falling masonry or crushed to death while maneuvering the massive stones.

© Getty Images

Broken limbs -

Those who survived their injuries often had to continue toiling with deformed bones and broken limbs.

© Getty Images

The result of chronic heavy labor -

We know this because skeletons unearthed during the excavation of the tombs of pyramid builders showed that many had been suffering from abnormal bony outgrowths known as osteophytes, which are caused by chronic heavy labor.

© Getty Images

Battered and bruised -

Skeletal analysis also revealed that the joints of numerous bones revealed severe wear and tear. In some cases, spines had been damaged. Severed limbs were commonplace, as were splintered feet.

© Getty Images

A short but productive life -

Pyramid workers died on average between 30 and 35 years old, depending on how fit they were or how much luck was on their side. If you were one of those who completed the task and reached the top of the pyramid (pictured), you could consider yourself fortunate.

© Getty Images

What else killed workers? -

For many years, scientists and historians believed that blunt force trauma was the principal cause of death among pyramid workers. But a recent study has revealed another killer: toxins.

© Getty Images

Toxic environment -

It appears the laborers who built these extraordinary structures were unknowingly exposed to dangerous concentrations of poisonous heavy metals, primarily copper and arsenic, on a daily basis.

© Getty Images

Chance discovery -

This unexpected discovery came about after archaeologists working in the streets of urban Cairo reached the bottom of the now-dry floor of Khufu Harbor.

© Shutterstock

Khufu Harbor -

They'd stumbled upon a vast, long-lost harbor complex built in honor of Khufu, which several thousand years ago was a thriving and active port located on a long-dead tributary of the Nile very near where the Giza pyramids were erected.

© Getty Images

Ancient Egyptian metallurgy -

After sediment was taken from the site of the old harbor, it revealed unsafe levels of copper and arsenic—byproducts of intensive metalworking activity.

© Getty Images

Metalworkers of old -

The ancient Egyptians were among the oldest civilizations to engage in metallurgical practices, and some of the most highly skilled craftsmen were metalworkers.

© Getty Images

Copper tools -

It's these same metalworkers who forged the copper tools required to chisel and shape the blocks of stone used in the construction of the pyramids.

© Getty Images

Contaminated byproducts -

Unfortunately, this produced contaminants in the water, soil, and air, which would have posed serious health risks to anyone hapless enough to be working and spending time in such an environment.

© Getty Images

Proof positive -

Scientists were able to carbon date the sediment extracted from the Cairo street to the regnal years of Khufu, Khafre, and Menkaure, the very same pharaohs who'd ordered the pyramids built.

© Getty Images

Harboring secrets -

Interestingly, through further analysis researchers found that the earliest traces of copper and arsenic discovered at the bottom of Khufu Harbor dated back to 3,265 BCE. 

© Getty Images

An ancient craft -

Their findings proved that metalworking began at Giza at least 200 years earlier than previously believed, and centuries before the great pyramids were conceived.

© Getty Images

A skill born out of prehistory -

Furthermore, it showed that the practice of metalworking dated back into the Predynastic era, which contradicts the previous belief that Giza had not been populated this long ago.

© Getty Images

Outstanding cultural legacy -

Working on the pyramids was indeed a perilous occupation, but what was created left an outstanding cultural legacy for humanity.

Sources: (New Scientist) (Live Science) (National Geographic) (Geology.com)

See also: Ancient sites worth visiting

© Shutterstock