Why Stonehenge Exists—and More of History's Greatest Mysteries

1 | The location of Genghis Khan's tomb

After the kingpin of the Mongol Empire, Genghis Khan, died in 1227, he asked to be buried in a grave with no marker or sign. Hundreds of years later, numerous teams of archaeologists have attempted to find the tomb, with no luck. However, on the heels of the discovery of Khan's palace in 2004, researchers believe that they might be close to discovering where this ancient symbol of power is buried.

2 | Why Stonehenge exists

If you're not already aware, Stonehenge is a prehistoric monument located in Wiltshire, England, with each stone standing approximately 13 feet high and seven feet wide. Built between 3000 B.C. and 2000 B.C., there are a number of theories as to why this formation exists. For one, some researchers believe, since the stones are aligned to the sunset of the winter solstice and the opposing sunrise of the summer solstice, that perhaps rituals were conducted here after its creation. Further, since there are a number of burial mounds surrounding the stones, some believe that it may have been used to celebrate the dead. However, since there is no written record of Stonehenge, it leaves its purpose a mystery.

3 | The disappearance of Jimmy Hoffa

Serving as the president of the International Brotherhood of Teamsters until 1971 and leader of the American Labor Union until 1975, Jimmy Hoffa was involved in mysterious organized crime activity that might have contributed to his disappearance in 1975. On the day he disappeared without a trace, Hoffa, then 62 years old, was reportedly meeting with two Mafia leaders: Anthony Giacalone and Anthony Provenzano. Despite the fact that both had threatened Hoffa in the past, there was no evidence that linked them to the scene of the crime. Since 1982, Hoffa has been declared dead without the solving of this mystery.

4 | The location of Cleopatra's tomb

Upon the siege of Alexandria, Egypt, and the death of Cleopatra and her lover, Marc Antony, in 30 B.C., both were rumored to have died by suicide. For thousands of years since, researchers, archaeologists, and fans alike have been clamoring to know what exactly happened to the lovers' burial place. While many excavations have been done to Alexandria and its surrounding cities, no sign of Cleopatra's tomb remains—just the mystery of the planet's first celebrity hanging in the air.

5 | The money pit on Oak Island

Oak Island in Nova Scotia, Canada, is said to be home to around $2 million in buried treasure, the extent of which has not yet been found. According to legend, the treasure was originally planted at the beginning of the 18th century by a member of Captain William Kidd's crew, who supposedly designed an elaborate set of instruction to access the buried loot. Despite the instructions advising treasure seekers to dig forty feet deep into the dirt to find the treasure, many have resisted digging that deep, claiming that superstition kept them away from the contents of the treasure. Currently, Rick and Marty Lagina of Michigan own the island and have permission from the Department of Natural Resources and the Department of Tourism, Culture and Heritage to finally unearth the treasure—though they have yet to do so.

6 | The message behind the Copper Scroll treasure

Discovered along with the rest of the Dead Sea Scrolls, this one actually differs from the rest as it does not contain a trace of literature but, instead, actually points out several places where various items made out of gold and silver are buried. And, while the directions in which to locate these items are clearly laid out in the text, some scholars believe that the scribe who wrote these directions down was simply copying from another tablet, and therefore made a few mistakes that make it impossible to decipher exactly where the buried treasure is hidden.

7 | The fate of the Ark of the Covenant

Also known as the Ark of the Testimony, this gold-covered wooden chest with a lid cover is described in the Book of Exodus as containing the two stone tablets depicting the Ten Commandments. Throughout numerous points in the past, different biblical figures were said to have used the ark, but its current whereabouts remain a mystery. While The Chapel of the Tablet at the Church of Our Lady Mary of Zion in Axum, a city in northern Ethiopia, claims to house the object, no proof has yet been established.

8 | The death of Natalie Wood

Film actress Natalie Wood captivated many for decades, until her mysterious death in 1981. While filming Brainstorm in 1981, Wood, her husband Robert Wagner, iconic actor Christopher Walken, and captain Dennis Davern were aboard a yacht near Santa Catalina Island. The next morning, her body was discovered, drowned, almost a mile away from the boat. While the others on board reportedly knew nothing of how she ended up in the water, she was found with bruises all over her body and an abrasion on her left cheek. Though her death was ruled an accident at the time, decades later, in 2011, the case was reopened and it was discovered that Wood had been flirting with Walken, leaving Wagner enraged. A year later, her death certificate read: "drowning and other undetermined factors." Now, in 2018, Wagner is considered the prime suspect in the case. Time will tell what truly happened to Wood, it seems.

9 | What happened to the passengers on the ghost ship, Mary Celeste

In 1872, the Mary Celeste, an American merchant ship, was discovered adrift and deserted off the Azores Islands, near Portugal. The ship had left for New York City just a month earlier, and when it was found, the cargo, containing denatured alcohol and all of the crew's possessions, was completely undisturbed. Though pirates were known to operate around this portion of the sea, many argue that they would have taken all of the cargo on board. Further, since the lifeboat was missing, researchers can conclude with some accuracy that perhaps the boat experienced mechanical problems, though, after further inspection, this argument is still questioned. More than a hundred years later, the disappearance of the crew on board the Mary Celeste is still a mystery.

10 | The authenticity of the Shroud of Turin

The Shroud of Turin, discovered during the Middle Ages, is believed to be the burial shroud that Jesus was buried in. However, many still debate over whether or not this is the actual burial shroud of Jesus, since a bishop in 1390 declared that the claim was false, and accused an unnamed artist of creating the blood pattern on the cloth that would have been consistent with Jesus' wounds from the crucifixion. Further, the Catholic Church has even hesitated to claim this cloth is the real thing, despite Pope Pius XII approving of the association between it and the devotion to the Holy Face of Jesus. To this day, the authenticity of this cloth continues to be questioned by many.

11 | The messages hidden in this ancient health guide

Discovered in 1912, this 15th-century Voynich manuscript containing what appears to be women's health advice, has been a mystery to scholars and historians alike, as no one has yet been able to successfully translate and interpret its text. What makes the text so interesting is that it contains pictures of alien plants, naked women, strange objects, and zodiac symbols that seem to hold no bearing to the area in northern Italy where it is thought to have originated. While many have tried to decode this text, we're still unsure of the secrets hiding in this ancient book of health advice.

12 | The fate of the Princes in the Tower

This expression refers to the disappearance of Edward V, King of England, age 12, and Richard Shrewsbury, the Duke of York, age 9, in 1483. After the death of their father, King Edward IV of England, the boys were taken to the Tower of London for protection by their uncle, Richard, Duke of Gloucester. However, soon after being taken to the tower, the boys disappeared and their uncle took the throne. Years later, a box of bones was discovered, hidden under the staircase in the Tower of London. And, though some claim that these bones belong to the boys, this has never been scientifically proven.

13 | The purpose of the Nazca Lines

The Nazca Lines are a series of large ancient geoglyphs in the Nazca Desert in southern Peru. Of the hundreds of lines delicately carved into the ground, around 70 are actually detailed images of animals, like birds, fish, jaguars, monkeys, and humans. Historians believe that these lines were created by the Nazca culture between 500 B.C.E. and 500 C.E. As for their purpose, there are many theories, ranging from religious to astronomical, that try to explain how the people could have benefited from these lines which can only be seen from the surrounding hilltops.

14 | The disappearance of the Irish Crown Jewels

The Irish Crown Jewels, also known as the Jewels Belonging to the Most Illustrious Order of Saint Patrick, were stolen from Dublin Castle in 1907, along with the collars from the five knights of the Order. Since the robbing, several rumors have charged the theft to various people, including an ancestor of famed explorer, Ernest Shackleton. To this day, the thief has managed to get away with their crime.

15 | The cause of the Greek Dark Ages

The Greek Dark Ages occurred between 950 and 750 B.C.E., though historians are still unsure of how this progressive culture fell into these harsh times. Prior to this time period, the Greeks thrived—maintaining farming systems and educational systems that greatly benefited the people. Then, all of a sudden, the population drastically decreased, leaving those still alive with fewer resources. Presently, historians still question why this sharp decline happened—and how.

16 | The disappearance of D.B. Cooper

Remaining as the only unsolved case in the history of air piracy in commercial aviation, a man only known as D.B. Cooper hijacked a plane for ransom money, amounting to $200,000, and then parachuted away to an unknown fate. Nine years after the event, in 1980, a boy found discovered a small cache of bills along the banks of the Columbia River, which renewed the interest in the case, but only deepened its mystery as well. Finally, in 2016, the FBI officially closed the case after decades of attempting to locate the man.

17 | The real story behind the Devil's Footprints

This phenomenon occurred in February of 1855 around the Exe Estuary in East and South Devon, England. One morning, after a heavy snowfall, the residents of the town woke up to large, hoof-like footprints covering a distance of up to 100 miles. These prints were called "The Devil's Footprints" because some believed that they were left behind by the cloven hoofs of none other than Satan himelf. Despite this theory, several historians have chalked this strange event to the strange hysteria of seeing many different kinds of animal prints at the time. Further, historians doubt that anyone could have actually tracked the footprints for that many miles in one day.

18 | The existence of Mothman

From 1966 to 1967, residents of Point Pleasant, West Virginia, reported seeing a moth-like creature the size of a large human flying around town. Some have even gone so far as to state that a sighting of the Mothman can bring about disaster, like the collapse of the Silver Bridge in town, which killed 46 people. However, many scientists have claimed that these sightings were merely hoaxes or just people with wild imaginations. To this day, we're still unsure of whether or not Mothman was ever as real as he was to the townspeople.

19 | Decoding the "Wow!" Signal

Serving as the strongest candidate for a SETI alien radio transmission ever received, this message, displayed above, was received in 1977 by Ohio State University's Big Ear radio telescope. Back then, this radio telescope was used to support the search for extraterrestrial intelligence. The signal appeared to have come from the global star cluster M55—which resides in the Sagittarius constellation—and, according to astronomer Jerry R. Ehman who interpreted the signal, bore all of the expected hallmarks of extraterrestrial origin.

However, whatever made Ehman circle these markings and write the famous "Wow!" is lost on him and the fellow researchers who have attempted to decipher this message for years. For years after detection, researchers have attempted to find any proof of it, but have failed. These mysterious circumstances have led many to the conclusion that this signal might have been attempted extraterrestrial contact.

20 | The identity of the Zodiac Killer

For the latter part of the 1960s and into the early 1970s, a serial killer known as the Zodiac Killer killed at least four men and three women in northern California. For nearly a decade, the killer sent letters to media outlets and police departments, detailing his killings and often threatening to engage in more violence in the future. As depicted above, he always signed the letters with a symbol that quickly became synonymous with the killing spree. Currently, authorities in the San Francisco area have reopened the case in order to test the envelopes the Zodiac Killer sent for DNA. As of yet, authorities have yet to identify one of the most famed serial killers in American history.

21 | The fate of the Roanoke Colony

The Roanoke Colony was the first attempt at a settling a permanent English colony in America—and one could say that it wasn't exactly a success. The colony was first established in 1585 in present-day North Carolina, though a majority of its occupants left a year later to return back to England with Sir Francis Drake. Just a year later, another expedition arrived to check on the occupants, but all they found was the word "CROATOAN" carved into a tree, with absolutely no trace left of the people at all. Hundreds of years later, historians believe that either the colonists were killed by Native Americans, or that perhaps their scant resources forced them into seeking shelter with the nearby Croatoan Indians, who had been kind to the colony since its birth.

22 | The identity of Jack the Ripper

Perhaps one of the most prominent serial killers of all time, Jack the Ripper killed five women and instilled a sense of terror on the streets of London in 1888. These attacks normally included abdominal mutilations, leaving the authorities and the public with a sense that the killer may have been a doctor or surgeon. During this time, authorities received hundreds of letters from people claiming to be the serial killer. One person even sent half of a preserved human kidney to the Whitechapel Vigilance Committee! However, despite years of scouring the streets for the killer, the true identity is still a mystery to this day.

23 | The existence of the Hanging Gardens of Babylon

Once considered one of the Seven Wonders of the World by Hellenic culture, the Hanging Gardens of Babylon were said to have featured an ascending series of tiered gardens with trees, flowers, shrubs, and vines. As its name suggests, the gardens were supposedly constructed in ancient Babylon, near present-day Hillah, Babil, in Iraq. While there is no definitive proof of its existence (at least archeologically, that is), five different writers around 290 B.C. spoke of its captivating beauty.

24 | The identity of the Black Dahlia killer

Serving as one of the most famous unsolved murders in American history, the case of the Black Dahlia still remains a mystery. The murder victim, aspiring actress Elizabeth Short, was found murdered in Leimert Park in Los Angeles, California, in 1947. The case became instantly famous for the gruesome nature of her body, which was found cut in half at the waist and badly mutilated. However, despite several attempts to solve the case, and a roster of 150 suspects, the killer was never found. Decades later, numerous books and films have been made, each presenting several theories as to who the killer may be. To this day, the public remains uncertain.

25 | The identity of the killer of JFK and RFK

As we all are well aware, the Kennedy family seems to be entirely too unlucky—and many are convinced that a conspiracy lies behind the ill fate of the family's two shining stars: Robert F. Kennedy and John F. Kennedy. The 35th President of the United States, John F. Kennedy, was assassinated on November 22, 1963, in Dallas, Texas. While the public knew his killer as Lee Harvey Oswald, numerous conspiracy theories claim that there are far too many inconsistencies in the case that the police filed, leaving many wondering if Oswald was hired by the CIA, or some other government organization. The assassination of his brother, Robert F. Kennedy, only five years later, fueled these conspiracy theories.

26 | The cause of Marilyn Monroe's death

Following along on this same trend, the death of icon Marilyn Monroe at the age of 36 in 1962, while then ruled as a suicide, still makes many wonder what truly happened to the film star. Many speculate that Monroe may have suffered the same fate as her friends in the Kennedy clan—that for some reason or other, she knew too much about something, and they had to silence her. However, many argue against this theory, as Monroe was going through an extremely trying time in her life, having suffered from depression and the loss of her role on Something's Got to Give earlier that year. No matter what the circumstances of her death may be, her legend will live on in infamy.

27 | The disappearance of the USS Cyclops

Built for the United States Navy several years before the first World War, the USS Cyclops and its 306 passengers disappeared without a trace in March of 1918, making it the single largest loss of life outside of battle in Navy history. Many historians believe that troubles with the ship itself might have contributed to it sinking in the waters of the Bermuda Triangle, while others (of course) believe that a conspiracy might be to blame.

28 | The secret meaning behind the Phaistos Disc

The Phaistos Disc was discovered on Crete in 1908, and thought to date back to the middle or late Minoan Bronze Age. Both sides of the disc contain a series of stamped symbols, whose purpose and meaning have left archaeologists and historians stumped for years. Though there are many different theories for what the disc contains, all agree that in order to truly know what treasures the disc holds, they first need to find more context with which to base their findings.

29 | The disappearance of Amelia Earhart

The first female aviator to fly solo across the Atlantic Ocean, Amelia Earheart mysteriously disappeared in 1937 on a trip around the world, despite being accompanied by skilled navigator Fred Noonan. As the pair were nearing Howland Island, a land mass situated between Hawaii and Australia, they stopped hearing voice transmissions from Earheart and Noonan. While numerous search efforts took place after the fact, no one has been able to successfully locate the plane or the bodies of Earheart and Noonan. Aside from theories that the plane crashed and sank in the waters surrounding the island (no plane has been discovered in this area), many conspiracy theorists believe that the pair might have survived and either crashed or safely landed on a number of islands outside of Howland Island. Either way, the whereabouts of Amelia Earheart is still unknown.

30 | Disappearance of the Indus Valley civilization

In current-day Pakistan and northwest India, a civilization known as the Indus Valley civilization came to become one of the earliest civilizations of the Old World, along with Ancient Egypt and Mesopotamia. At its peak, the Indus Valley had more than five million occupants, resulting in a sophisticated system of urban planning that showed great skill and intelligence for that era. However, around 1500 BC, the people and culture seemed to almost vanish into thin air, with some scholars suggesting that it might have been due to an Aryan invasion or other ecological factors like earthquakes or climate change. Either way, most historians are still unsure of what sort of catalyst could make an entire culture disappear.

31 | The mystery of the Bermuda Triangle

Also known as the Devil's Triangle, this section of the North Atlantic Ocean, between Florida, Bermuda, and Puerto Rico, has witnessed a suspiciously high number of aircraft and ships that have disappeared under mysterious circumstances. Over the years, many conspiracy theorists have hypothesized that the waters might contain the lost city of Atlantis, or that, perhaps, aliens could be to blame for the mystery swirling in the waters. However, years later, these theories have been largely disproved.

32 | The location of the lost city of Atlantis

First mentioned (or, in fact, contrived) by Plato, the city of Atlantis has become a monument to all lost ancient cities, leaving many wondering if it exists at all. While some historians believe that this city is fictional, others have attempted to uncover its location, thousands of years after its supposed fall into the ocean. From the Mediterranean Sea to the icy cold waters surrounding Antarctica, explorers have all tried to be the first to find this city that the deities rejected, and cast into the ocean to forever remain a mystery to all.

33 | The existence of the Loch Ness Monster, Yeti, Big Foot, and Sasquatch

While they may inhabit every corner of the globe, the one thing that brings all of these creatures together is the heavily-debated proof of their existence. In fact, Big Foot, the large, bear-like animal that stands on its hind legs and resembles a human, has been seen in 49 states in America. According to scientists, all of the circumstances behind the "proof" gathered, claiming that these animals exist, is false, and likely the work of people attempting to hoax the public. If you're still convinced that these animals exist, take a trek into the woods to see for yourself.

34 | The story behind the Tarim Mummies

A number of mummies of Caucasian descent were discovered in present-day Xinjiang, China, with historians dating back their deaths to around 1800 B.C.E.—thousands of years before it was assumed that a Caucasian race of people ever populated that part of Asia. Though some scientists have attempted to disprove their time of death, many have corroborated this finding, and point to the fact that ancient Chinese texts often mentioned leaders with blue or green eyes and long, red or blonde hair. While this is a detail that many historians used to scoff at, many are now reevaluating their understanding of human migration during that time period.