10 Ancient Mysteries That Aren’t on Your Radar–but Should Be

There are so many unsolved mysteries out there in the world. Who killed JonBenet Ramsey? Whatever happened to Amelia Earhart? Will we ever learn the true identity of D.B. Cooper? And on and on. But (relatively) recent unsolved dramas aren’t the only things that keep us awake at night. Ancient mysteries have us scratching our heads and pondering what life must have been like back then, too.

In this list, we’ll take a deep dive into ten ancient unsolved mysteries that have confused and frustrated archaeologists and historians for hundreds (and sometimes thousands) of years. Even better, these ten ancient conundrums very often escape the history books—so you’re sure to learn something new as you scroll through. So, come on down the rabbit hole with us! Let’s get weird about the ancient world…

Related: 10 Unsettling Unsolved Mysteries from the Old West

10 The Hellenikon Pyramid

It’s easy enough to label the Egyptian pyramids as ancient mysteries, at least in terms of how those massive structures were built. But Egypt’s ancient society wasn’t the only one that built pyramids. Take the Hellenikon Pyramid in Argolis, Greece, as the best non-Egyptian example of this.

First, it was built thousands of years ago. Some historians believe it was constructed roughly around 2720 BC, which truly boggles the mind. That construction date would make it significantly older than all of the Egyptian pyramids, too—so right off the bat, archaeologists are fascinated with how the Greek pyramid could have possibly been constructed with the tools and engineering know-how of the time.

Beyond that, it’s also completely unclear why the Hellenikon Pyramid even exists. Some historians have theorized that a very significant ancient battle took place on the site, and the pyramid functions as some kind of temple to honor the fight and its dead soldiers. That’s probably a reasonable theory, but sadly, it’s just that—a theory. Nothing has ever been found inside the walls of the now-crumbling pyramid to confirm its use as a tomb or memorial location.

In the end, remarkably little is known about the Hellenikon Pyramid. That it was built so long ago and so far before the Egyptian pyramids were created only deepens the mystery. Considering that the rest of Greece doesn’t hold any similar pyramids (or at least none that have survived the test of time), it is even more bizarre.

Why is it there? What was it used for? How was it even built in the first place? And why is it the only one in the region? At this point, it seems like we’ll never know.^[1]

9 The Rongorongo Writings

Everybody knows about those massive stone face statues that sit along the ground on Easter Island in the South Pacific Ocean. Of course, it’s still a mystery why they are there and how they were made. But that’s at least a well-known mystery. As it turns out, Easter Island is home to a much more bizarre second ancient mystery that has thus far mostly eluded widespread attention: the so-called Rongorongo writings.

ThEse writings are a series of intricate glyphs carved into stone that appear to be a very (very, very, very) early form of the written word. And considering just how removed Easter Island is from the rest of the world, it would appear as though its inhabitants literally invented writing on their own and in complete isolation.

The Rongorongo writings were first discovered (by Western people, at least) by a man named Eugene Eyraud in 1864. But the glyphs predate Eugene’s discovery by at least seven or eight centuries—and likely even more than that! Without any insight into how they got there, how these words and symbols were created, and in what way they came to be standardized, modern experts are completely in the dark. Basically, we know just as much now about the Rongorongo writings as Eyraud did on the day he first discovered them!

And here’s the other strange thing: scientists and archaeologists haven’t been able to decode the glyphs. At all. Because Easter Island was so isolated, the language used in the table writing isn’t obviously related to any outside culture from anywhere nearby. It would appear that the writings are from a now long-lost language that will almost certainly never be revived. But if you feel like you can decipher codes and figure out puzzles, by all means, have at it!^[2]

8 The Nazca Lines

We all know about crop circles: those sprawling patterned crop designs that seem to pop up every so often when a prankster (or an alien, maybe!) gets a little goofy. But crop circles have more or less been debunked by now. And they aren’t ancient mysteries, anyway. No, the ancient version of this is far creepier and more uncertain: the Nazca Lines. This series of massively long lines is set out in huge areas of the dry deserts and plains of southern Peru.

Nobody knows why they are there, exactly how they got there, or what purpose they served—beyond the assumption that they likely held some religious value for the now-long-gone Naza culture. And the lines are incredibly ancient, too. Historians have estimated that the Nazca Lines were created sometime between 500 BC and AD 500.

In total, there are more than 100 of these huge glyphs, all of which can be readily seen from the air. That they were created so perfectly by people who were stuck on the ground and didn’t have the technology to fly planes (uh, we think?) is mesmerizing. As far as the specifics, the lines create all kinds of easily recognizable shapes: humans, birds, monkeys, fish, and even a jaguar. But why? What was the purpose?

Some archaeologists have theorized that they could be seen by approaching sailors landing from the sea, and they were directions to alert them where to come to shore. Others believe there was a religious component to the entire thing. Still, other archaeologists wonder whether the Nazca Lines might have been some kind of long-ago warning system about danger and death to come. Well, that’s just creepy…^[3]

7 The Sajama Lines

Let’s keep right on going with some weird South American lines. Over in the western region of nearby Bolivia, the so-called Sajama Lines rival the aforementioned Nazca Lines for ancient mystery supremacy. The Sajama Lines were first discovered (again, by Westerners) in 1932 by an explorer named Aimé Felix Tschiffely. In total, these lines number in the thousands.

All of them are between 3 and 10 feet (1 and 3 meters) wide on their own, and they are all connected in an intricate web of sorts. In sum, the total area covered by the Sajama Lines is nearly 8,700 square miles (22,532 square kilometers). So we’re talking about thousands of lines over a truly massive area. Taken together, they are by far the largest archaeological site in South America—and one of the biggest ancient world sites on the entire planet. Cool!

Stop us if you’ve heard this one before, though: Nobody has any idea why they were made, what purpose they served, or even exactly how they were created. Obviously, an indigenous group that lived near the lines long ago would seem to be the creators. But beyond that assumption, little else is known about the purpose they serve. That they are so straight and specifically laid out (and that they have withstood the test of time when it comes to still being around today) has only added to the mystery.^[4]

6 The Diquis Delta Stone Spheres

Ever since they were first discovered by archaeologists in the 1940s, Costa Rica’s so-called Diquis Delta Stone Spheres have been a complete and total mystery. Nearly a century ago now, the United Fruit Company was pushing deep into the jungles of Costa Rica. They were initially there in search of new agricultural opportunities to conquer, farm, and exploit for riches.

As their employees dove deep into the jungle forests, they came across a series of massive and round stone spheres. Confused, they called in a set of archaeologists to study them. And even with the experts on hand, the confusion only continued! The stones are set out in the forest in all kinds of different shapes. Some are just a few centimeters in diameter; others are one or two meters in diameter and can weigh as much as 16 tons! That they are spherical and found as nearly perfect circles only adds to the mystery, too.

How did an ancient culture make such awesome and smooth spherical stones? How long did it take? And what purpose did they serve at the time they were created? Nobody knows much at all about the stones. Today, many of them have been transported around to other parts of Costa Rica, and some are owned privately by collectors and history buffs alike.^[5]

5 The Hypogeum of Ħal Saflieni

Malta’s Hypogeum of Ħal Saflieni was only first discovered by modern explorers in 1902. Seen as a sanctuary and perhaps a burial place and/or house of worship of some kind, its purpose is ultimately unknown. But what we do know about it is very cool: It is the only still-preserved example of an underground labyrinth structure across the entirety of Europe.

While archaeologists don’t know pretty much anything else beyond that, they have been able to figure this out: the Hypogeum was in use from 4000 BC to about 2500 BC. Underground or not, that makes it an insanely old structure—which is even cooler considering the fact that it is so well preserved today.

The subterranean building has three levels to it, all of which are carved extremely carefully out of the rocks around it and painted in ornate designs. And the most chilling (and cool) part of the Hypogeum is the so-called “Oracle Chamber.” In that special chamber, words that are spoken at a normal talking volume are amplified one hundred times over, thanks to the room’s unique acoustics.

In fact, just speaking in a normal voice in the Oracle Chamber allows you to be heard through the entirety of the massive Hypogeum. Historians don’t know whether that fascinating design feature was intentional, but honestly, how couldn’t it be?^[6]

4 The Yonaguni Underwater City

Even though many of us have heard of Atlantis, did you know that there’s a Japanese version, too? Submerged just off the coastline of the Yonaguni Jima area of the East Asian nation is an underwater city known as Yonaguni. The area is a sprawling metropolis—or, at least, it was when it was actually in use.

According to archaeologists, the long-dead city is believed to be at least 5,000 years old. There’s plenty we don’t know about it, unfortunately. That’s because it was only first discovered by a team of divers in 1995. So, with not even 30 full years of research and knowledge under our belts, the modern world has very little clue about what went on at the Yonaguni underwater city!

At first, experts thought that the city actually wasn’t a city at all. Instead, they believed it to be a series of bizarre natural rock formations. However, nearly all of these rock formations intersect each other at perfect right angles and run across very specific straight lines. The lines are far too straight to be natural, obviously. Plus, deeper exploration of the underwater city has led divers to discover that there are large stone gateways, vaulted towers, carved stairways, and even meticulously laid-out stone streets!

Of course, the city almost certainly didn’t fall into the sea like Atlantis is said to have done. And it wasn’t inhabited by some weird half-human, half-fish, or mermaid underwater species of the ancient world, either. What most likely happened is that the Jomon people—who were the original indigenous group native to Japan way, way long ago—lived in the city as they did many others around the area.

Then, over time, sea levels rose, and the city was eventually claimed by the ocean. The fact that the Yonaguni underwater city is still so well-preserved is fascinating, though. It’s an important site for archaeologists to learn about ancient people. If only they could figure out anything definitive about it!^[7]

3 The Bog Bodies

The peat bogs of northern Europe have been home to a series of remarkably (and, if we’re being honest, disturbingly) well-preserved human remains that stretch back thousands of years. The remains have come to be known as the “bog bodies” of Europe. And even though they were first discovered in the 18th century, they are far older than that.

Some of the bodies found in Denmark and other nearby areas have even been forensically dated using modern technology. Those that have come back with results indicate that these long-dead humans may have lived as far back as 8,000 BC.

Of all the bog bodies of northern Europe, the most famous one is called the “Tollund Man.” He was only first discovered in 1950 by two Danish farmers in a small town. Archaeologists descended quickly because he was far better preserved than any other ancient human body in the area. With time, they managed to nail down the Tollund Man’s time period to the 3rd century BC during the pre-Roman Iron Age, which was sweeping across northern Europe. He was so well-preserved, in fact, that the contents of his stomach were critical in learning more about when and how he lived. Talk about long-expired food!

Here’s where the bog bodies turn thick with mystery, though: Nobody can explain why or how they were dropped in the boggy area in the first place. The bodies vary across age, sex, and apparent social standing based on their clothes and health histories. But all of them appear to have one commonality: that they were executed and then thrown in the bogs. Were they sacrificial deaths offered up to deities? Were they criminals or otherwise social outcasts who were deemed to die? Nobody knows.^[8]

2 The Sumerian King List

Let’s go all the way back to the 3rd millennium BC and a document that has come to be known as the Sumerian King List. This document (well, really, it’s a stone tablet that is covered with carved writings) is exactly what it sounds like. It offers up a complete list of all the Sumer kings, their times in power, the locations of their seats of power, and where they fall in their respective dynastic lines.

Taken just in that regard, then, the Sumerian King List isn’t all that interesting. After all, it’s just a list of rulers. Should we start naming the presidents of the United States of America? Because that ancient list is pretty much the same thing. Booo-ring!

But here’s where the Sumerian King List gets crazy. The other stories that are inscribed alongside the list suggest god-like situations at play. Along with listing out all the Sumerian kings, the document describes the Great Flood, as well as the tales of Gilgamesh. Those and other stories laid out in the list have often been seen as fables and not actual historical events.

However, this King List is so detailed in its descriptions (and so darn old, to boot) that historians now wonder whether those so-called fables actually did happen. In turn, that would mean that many of the Old Testament stories from the Bible are actually true. Therefore, some of the kings listed are actually gods—or, at the very least, demi-gods!^[9]

1 The Devil’s Bible

Technically known as the “Codex Gigas,” the so-called Devil’s Bible is a massive book from the medieval era. It was written in the 13th century, purportedly by a monk who is said to have made a deal with the Devil just to finish it. According to legend, that monk broke his solemn religious vows at some point during his life.

Ultimately, he was sentenced to be executed. But he was said to have cut a deal with the local monastery that if they let him live, he would write a book that contained all the human knowledge ever determined—in just one single day. The other monks at the monastery supposedly thought that sounded pretty good, so they got on board with it. Then, this imprisoned monk is said to have turned around and made a second deal (with Satan) to actually write the book. Clearly, this monk was a hell of a wheeler and dealer!

Now, while that legend is likely based in fiction far more than fact, the Devil’s Bible is fascinating because it appears to have been written by only one person—and in a very, very short amount of time. The book is massive, and it was created out of more than 160 animal skins used as primitive paper and binding.

It’s so heavy that one person alone can’t even lift the thing! And it has a little bit of everything inside. The complete Latin translation of the Bible, the works of Hippocrates, the Cosmas of Prague, hundreds of medical formulas, dozens of texts on exorcisms, and even a large image of the Devil. Because, of course, right?

However, experts don’t have any idea who actually wrote it or how they were able to finish it so quickly. Even more bizarre, historians and textual experts have determined that about a dozen pages of the manuscript are completely missing. And that’s only deepened the mystery as to why the book exists and how it came to be!

Theorists claim those missing pages were pulled out because they contained secret Satanic rituals and revelations. Some say one could have even conjured up the Devil himself in those long-gone pages. But by this point, we’ll never know exactly what went missing.^[10]