There were civilizations that existed before us but were destroyed by natural calamities. The ancient monuments and technologies which we find amusing were created by humans only. But with countless wars and no documentation in the modern language, we lost a lot of knowledge about the previous civilizations.

Historians digging up pieces of evidence of ancient civilizations believe that ancient humans were much more advanced than the modern ones. The existence of man-made marvels such as the pyramids of Egypt, Nasca Lines, Stonehenge, Teotihuacan, and face on Mars have been a topic of curiosity for several decades. We still have centuries old monuments standing tall and proud as modern buildings continue to collapse with the slightest issue. Knowing how these things were made would have been of great use today.

From a Roman birth control drug in 27 BC to a device that could predict celestial events, it seems like the ancient humans knew a lot more than we give them credit for. While we have become too dependent on chemicals and digital gadgets, the ancient humans only had a few hand-made gadgets and elements found in nature.

While we have understood and analyzed a lot of technology invented by our ancestors, many of it still remain a mystery to us. Here are 15 pieces of ancient technology that we still don’t understand.

15. Nimrud Lens

Nimrud lens is a 3000-year old piece of rock crystal that was found in the palace of Nimrud, Iraq by Sir John Layard in 1850. It is said to be made during 750-710 BC. Scientists have proposed a theory that this lens was used by ancient Assyrians as a part of a telescope, considering their knowledge in astronomy.

The lens is slightly oval and roughly ground on a lapidary wheel. It is believed that the ancient Assyrians considered Saturn a god, surrounded by a ring of serpents. This in turn proves that Galileo wasn’t the first person to create a telescope.

14. Antikythera Mechanism

The Antikythera mechanism is an ancient Greek device used to track the movement of the sun, the moon, and the planets to predict celestial events and for other astrological purposes. It was found in the 1990s by divers around the coast of the island of Antikythera. Scientists believe that this device belongs to the 1st or 2nd century BC.

The device’s purpose is not fully understood, but its construction has puzzled scientists over the years. It is often referred to as an analog computer because of its ability to calculate solar years and lunar phases.

13. Greek Fire

The Greek Fire is perhaps the most famous lost technology in human history. It was used by the Byzantine Empire in the 11th century to help Constantine against Arab invaders. The chemical contents of the Greek Fire are yet to be discovered.

However, a modern theory proposes the Greek Fire to be made of petroleum, quicklime, niter, and sulfur. The Greek Fire was sticky and would even burn on water, much like Wildfire in the Game of Thrones. It could only be extinguished using a mixture of vinegar, sand, and urine.

The Byzantines were secretive of this technology and it died along with the empire.

12. Telharmonium

The world’s first electronic musical instrument, the Telharmonium was truly one of a kind. Developed by Thaddeus Cahill in 1897, it was a large musical organ which produced creative synthetic musical notes by using tonewheels. The sound created was automatically transferred to the loudspeakers through wires. The musical instrument is said to be weighing 200 pounds and big enough to fit an entire room.

After it’s initial success, Cahill had big plans for telharmonium. Sadly, the device was too modern for its time, consumed a humongous amount of energy which the early power grids couldn’t handle, and cost a whopping $200,000.00.

11. Nepenthe

An anti-depressant drug, nepenthe was said to be a drug of forgetfulness in ancient Greek literature. It is also frequently mentioned in Homer’s Odyssey as well. While it originated in Egypt, the Greek would usually treat the bereaved with this drug. Some argue that the drug is purely an art of fiction, but some feel otherwise. Because of its antidepressant properties, it is compared to opium.

This is one technology which is probably still around today, but researchers are unable to pinpoint it. Some researchers feel it can either be opium, wormwood extract, or scopolamine.

10. Vitrum Flexile (Flexible Roman glass)

Vitrum Flexile was created during the reign of Roman Empiror Tiberius Caesar. It was invented by Petronius in 63 AD who presented the vessel to Caesar and asked him to hand it back to him. When Petronius threw it on the floor, it didn’t break but only dented. The inventor then molded it back to its original shape. Not recognizing the genius, Caesar beheaded the inventor fearing devaluation of precious metals.

Another version of the story told by Dio Cassius portrayed the inventor as a magician. When the vessel was thrown on the floor, it shattered, and the inventor fixed it with his bare hands. A company named Corning introduced a flexible glass similar to Petronius’s in 2012.

9. Stradivari violins

One of the most famous lost technologies is the process of making Stradivari violins. The violins along with other musical instruments like violas, cellos, and guitars were made by the Stradivari family of Italy between 1650-1750. The Stradivari violins are a prized possession today and cost over a hundred thousand dollars. Only 600 of them still remain as of today.

The technique to build the Stradivari violins was a family secret and only known by Antonio Stradivari and his sons, Omobono and Francesco. The secret died with them. After studying the violin, researchers have established a hypothesis claiming that it is the density of a particular wood that produces the unique sound and resonance but no one knows for sure.

8. Archimedes’ Heat-ray weapons

Heat-ray weapon was a war weapon made by Greek mathematician Archimedes. It was made of bronze and would reflect sun rays in a destructive manner. With this weapon, it became possible to burn the entire Persian fleet in one go. Archimedes’ weapon motivated the Mythbusters of Discovery Channel to replicate it in 2004. They were unsuccessful in their attempts and declared it a myth.

In 2005, MIT students were successful in recreating the heat-ray weapon and combusted a 2,200-year old replica in San Francisco harbor. In 2001, Defense Advanced Research Projects Agency (DARPA) unveiled a heat-ray weapon which used microwave rays to penetrate the victim’s skin heating it to 130 degrees Fahrenheit.

7. Roman concrete

Roman concrete was used for construction during the late Roman Republic until the fall of the Roman Empire. The modern cement used today has a life of 80 years, but Roman concrete seems ageless. Famous Roman structures such as the Pantheon, the Colosseum, the aqueducts, and the Roman Baths still stand proud today.

While researchers were able to find the secret ingredient in the Roman concrete, which is volcanic ash, the process of creating it is still unclear. The biggest problem being, it takes much longer to dry as compared to the modern cement.

6. Damascus steel

Used in the Middle East around 1100-1700 AD, the Damascus steel was a very strong metal. It was mostly used to make knives and swords. It is known to cut rocks and other metals especially swords of softer metals cleanly into a half. It is believed to be made of wootz steel found in Sri Lanka and India.

Swords from Damascus steel were made by combining soft iron and cementite. The technique was lost around 1750 AD. It was probably because the smiths who made the swords didn’t have a specific recipe to create them and just went with their instincts.

5. Lycurgus cup

The Lycurgus cup is a glass chalice made with dichroic glass that would change colours depending on the light passing through it. This fascinating art piece reveals the knowledge ancient people had about nanotechnology. The cup portrays the defeat of Emperor Licinius by Constantine in 308-24 AD.

When light passes through the cup, it changes color from opaque green to a fiery translucent red. The cup contains colloidal gold and silver, giving it these unusual optical properties. A research team from University of Illinois is trying to build a more sophisticated structure based on the science applied to make the Lycurgus cup.

4. Viking compass

A mysterious sun stone is mentioned in the Norse sagas which showed sailors the path when the sun went down. The Viking compass had the accuracy of today’s GPS. Until now it was considered to be a myth. But researchers have recently discovered a special crystal which proves the Viking compass theory to be true.

The crystal was first discovered in a sunken Elizabethan ship in 1592 near the Channel Island (between England and France). With the help of this stone, the Vikings successfully navigated from the North Atlantic to the New World and even further. By the way, GPS wasn’t invented till the Second World War.

3. Metal plating in Qutub Minar complex

An art of ancient craftsmanship, the metal plating on the iron pillar that stands in the Qutub Minar complex in Delhi, India is rust-free. The iron pillar was made during the Gupta Dynasty in 4th century AD. It weighs 6.5 tons and is rough a few hundred centimeters from ground and has a smooth surface at eye level.

Researchers believe that it is the high amount of phosphorus in the iron used to build the pillar that has kept it rust-free. This portrays the exceptional metallurgical skills possessed by ancient Indian craftsmen. The pillar shows no signs of damage, except a fissure caused by a cannonball strike.

2. Construction of the pyramids in Giza

The pyramids of Giza have fascinated people for ages. The Great Pyramid built in 2550 BC is thought to be the largest structure created by mankind. Scientists have revealed that it took around 20 years to build the Great Pyramid. Despite all the research done, scientists are still unclear how the pyramids were built. Some believe that the pyramids were made by a much more advanced ancient civilization 4500 years ago.

The pyramid is made using 2.5 million rocks, each weighing 2.5 to 15 tons. With the lack of resources, it would have been impossible to lift them using just wood ramps so it was probably done manually.

1. Molten rocks of Sacsayhuamán

Sacsayhuamán is located in the City of Cuzco, Peru. The stones in the zigzag patterned wall are so heavy that even modern machinery cannot move them as each one of them weighs 140 metric ton. According to researchers, the granite wall shows evidence of exposure to high temperatures, making the outside surface glossy and smooth.

The builders had some advanced tech device which would melt stone, place, and allow them to cool and harden.The wall is so compact that grass or steel cannot slide between two boulders. No mortar is used to join the stones. And that is why, the rocks still remain a mystery.