10 Mind-Bending Puzzles Humanity Still Can't Solve

#10: Were the Hanging Gardens of Babylon Real? - Age of Antiquity

For thousands of years, people have wondered about the majestic Hanging Gardens of Babylon. The ancient city is located in modern Baghdad, and we’ve found tons of relics and ruins from when the Babylonian Empire stood tall. Legends claim the Hanging Gardens were built around 600 BC, but they’d completely vanished by the time Jesus was born. Archaeologists have found no evidence that they ever existed, despite finding other pieces of Babylon. Some scholars believe they may be buried beneath the Euphrates River, which has moved over time. Theoretically, if it existed, evidence is out there; we just have to know where to look.

#9: Roman Dodecahedrons - 1739

Since 1739, archaeologists have discovered these mysterious shapes across ex-Roman provinces, except Italy, peculiarly. They all date from between the 2nd and 4th centuries AD. Ever since we first uncovered one, scholars have been debating what they were used for. There’s no theory that’s widely accepted, making it a complete mystery. Some think they were used for measuring distances. Others believe they were used for spool knitting, computing mathematics, or that they were simply toys. Maybe they were made just to confuse future historians. None of our written sources ever mentions them, but with so many available, surely we have all we need to solve the mystery.

#8: The Phaistos Disc - 1908

This peculiar clay disc was discovered on Crete in 1908. We believe it was created in the 2nd century BC, but we have no clue why. It likely belonged to the Minoan civilization, but its specific origin is still debated. The disc is decorated with 241 signs, of 45 different varieties. These symbols didn’t line up with our expectations of Cretan writing, leading historians to briefly believe it was a hoax. Now, it’s widely considered authentic, but we still have no clue what it says, why it was made, and what it was meant to do.

#7: The Copper Scroll Treasure - 1952

In the mid-20th century, the Dead Sea Scrolls were discovered in Palestine’s West Bank. They’re ancient Jewish manuscripts, including the Copper Scroll. As the name implies, it’s written on metal, but not copper. It’s unique from the rest, since it’s a list of 64 locations where one may find buried treasure. Archaeologists believe it came from roughly the first century AD. This means it likely comes from the Jewish-Roman wars, so this was theoretically written to prevent the Romans from capturing their valuables. We think it came from a temple, but we have no idea if the treasure is real or where it is. We’ll only know for certain when we find it, but that’s easier said than done.

#6: Hilbert’s Problems - 1900

In the year 1900, German mathematician David Hilbert proposed 23 problems to be solved. Over a century later, they’re still not completely solved. The most problematic of these is the 8th problem, also known as the Riemann hypothesis. It’s arguably mathematics’s greatest problem. If you want to get rich, then there’s $1 million up for grabs if you can solve it. The issue surrounds a specific mathematical function, the Riemann zeta function. Hilbert proposed that all non-trivial zeroes of this function lie on a singular vertical line. Slowly, researchers are getting closer to solving the issue, but some believe it’s false and not worth their time.

#5: Voynich Manuscript - 15th Century

Carbon dating says this codex was first written at the start of the 15th century. It’s a 240-page-long book, full of peculiar writings and illustrations. No one knows what language it is, meaning historians have no idea what the book’s about. Illustrations allow us to divide it into four sections, each focused on botany, astronomy, balneology, and pharmacology. There’s a final fifth section, but since it’s without pictures, it’s a total mystery. This has led many to believe it’s a hoax, and that its contents are entirely nonsensical. Either way, we generally believe its origin is medieval, but we’re yet to truly comprehend its meaning.

#4: Zodiac Killer’s Ciphers - 1969-74

Over half a century after the Zodiac Killer was terrorising San Francisco, we still have no idea who he was. Between 1969 and 74, he sent haunting letters and ciphers to the police and the media. There were four ciphers in total, but only two have been solved. The first was figured out in 1969, then the second in 2020. Deciphering these messages has been made more difficult by the killer’s atrocious spelling. The first cipher had 408 characters, the second 340, then the final two had 13 and 32. You would hope that made them easier to solve, but that’s not been the case. Maybe some day we’ll figure them out, but it’s uncertain whether they’ll reveal the killer’s identity.

#3: Linear A Script - ~1800-1450 BC

Once again, the elusive Minoans of Crete make it onto our list. We know they spoke a language called Minoan, but this language is barely understood. It was first written with Cretan hieroglyphs, then with the Linear A writing system, and finally with the Linear B system. We have deciphered the latter script, but Linear A is a total mystery. It was primarily used in religion and palaces, becoming predominant in the 2nd millennium BC. One of the main reasons it’s such a challenge is because of how few texts we have. For Linear B, we found roughly 6000, but for A, we’ve only found 1400. Theoretically, it can be solved, but that may not be within our lifetimes.

#2: The Somerton Man - 1948

In 1948, the body of a man was found on a beach near Adelaide in Australia. He was nicknamed the Somerton Man, and his identity has been a mystery since. In his pocket, there was a piece of paper which had the Persian phrase for “it is finished” inside. It had been torn from a poetry book, which was found, and included a coded message and mysterious telephone numbers. In 2022, researchers successfully found his identity. His name was Carl Webb, an electrical engineer born in 1905. That’s only a small piece of the mystery; however, it’s still unclear what caused his demise and what the code meant.

#1: Indus Script - ~2800-1900 BC

The Indus Valley Civilisation was one of the earliest human civilisations ever discovered. They existed in North Western India, along the Indus River, and survived from 3300 all the way to 1300 BC. Archaeologists have discovered peculiar scripts in the civilisation’s remains. It’s unclear whether they’re a writing system or not. This is made harder by the fact that we have little understanding of the Indus language. If you can manage to crack the code, then you can be rewarded $1 million by an Indian chief minister. Figuring out their language would allow us to learn tons of new things about their society and customs, which are currently an unattainable secret.

Do you think you’ve got any plausible theories that may explain some of these puzzles? Let us know in the comments section!