▲Koko was a gorilla who shocked the world with her sign language ability. She could communicate with people through sign, and said some profound statements along the way.

▲Voynich was a book dealer who bought the text in 1912. Some say it hails from Northern Italy, and codebreakers have worked hard to figure it out, but there's been no leads as to what it means.

▲Named the "Wow!" signal, it has never repeated, and there haven't been many credible answers for the occurrence. Regardless, it remains the biggest indicator that aliens are out there.

▲Reports of alien sightings have long mystified historians, but in the late '70s, we received probably the most credible evidence. A 72-second long signal was recorded by Ohio State University's Big Ear Radio telescope.

▲As with Mozart and Genghis Khan, no one knows where Cleopatra's tomb is located. Many believe she was buried along with her lover, Antony, but the exact location has never been determined.

▲Penny Patterson, an animal psychologist, revealed that Koko talked about the afterlife. When asked "where do animals go when they die?" Koko said "a comfortable hole." The answer has baffled many people, and sparked philosophical debates.

▲Suddenly, Amato became musically gifted, and started composing music for piano. He's since become a musical savant, and scientists struggle to explain how it all happened.

▲Over 500 years ago, a text was written in an unknown language by an unknown author. The handwritten text is known as the Voynich manuscript, named after Wilfrid Voynich.

▲In recent years there were reports that archaeologists broke through and found it, however the location of the long-lost burial site remains a mystery.

▲Once Joyita was found, it was clearly above water, but there was not a single soul onboard. 25 people reportedly set sail on the boat. However, reports say none of the crew were found.

▲There's something about islands that have always inspired intrigue and mystery. The island of Bermeja (seen above the letter "X") has been an entertaining source for stories, mainly because it doesn't exist.

▲Legend has it that back in 1930, fur trapper Joe Labelle happened upon the village, finding nothing but dead sled dogs and no one else. A conclusive explanation has never surfaced.

▲The mystery of Angikuni Lake has long mystified historians. It was once the location of an Inuit village, the inhabitants of which reportedly vanished, never to be found.

▲Joyita was a merchant vessel which is also the subject of years-long mystery. Back in 1955, the boat vanished from the South Pacific. Here's the hook: the ship was engineered not to sink.

▲Crazily enough, Bermeja appeared on maps right up until the 20th century. There have been many theories about the island. One of which suggests that the island did exist, but was destroyed by the CIA for economic reasons.

▲In 1876, a woman named Mrs. Crouch experienced an unbelievable event of natural phenomena. While sitting on her porch, she observed red meat rain from the sky.

▲Harold Edward Holt served as the Prime Minister of Australia from 1966 until… well, he disappeared off the face of the Earth.

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Holt was out for a swim with four friends at the remote Cheviot Beach. Suddenly, his body was rapidly taken by the sea, and witnesses saw him vanish. A huge search was conducted, but nothing was found.

Sources: (Bored Panda) (Reader's Digest)

▲When her tomb was found, they discovered a body that stayed preserved for more than 2,000 years after her death. She still had hair, eyelashes, blood in her veins, and melon seeds in her stomach. Scientists were baffled by the preservation.

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This one's pretty gruesome, so be warned before you go on Google Images. Xin Zhui was a royal figure who died in 163 BCE in China. Pictured is a recreation of her appearance.

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Known as Hector the Convector, the cloud has been called a "consistent thunderstorm," and meteorologists have mused about its many causes.

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Scientists have also been baffled by Hector, a thundercloud that forms nearly every day, over the Tiwi Islands in Australia.

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They were mostly US$20 coins, amounting to US$27,980. However, they are valued at US$10 million today. The The U.S. Mint said they had no information linking the hoard with any money manufacturer, and the couple kept the coins.

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Back in 2013, a couple discovered a large can filled with over 1,400 gold coins. The question is, who did the treasure belong to? Funny enough, the discovery was made in Gold Country, California, and the coins were roughly dated to the Gold Rush era.

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There are hundreds of historical objects with ancient writings and messages. However, the Phaistos Disc is unique, since no one can read what on Earth it says.

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Some say it's a board game, others claim it's a calendar. However, the Bronze Age object has never been properly defined. It was discovered in Phaistos, Crete.

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It was initially thought that it was some sign of God, or a plague. Scientists have investigated, but no clear answers have been found. Some say the meat was regurgitated by vultures, who may have been startled into flight just after feeding.

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Derek Amato shocked the world in 2006, when he basically became a musical genius overnight. When he was 39, Amato dove into a shallow swimming pool and suffered a serious head injury.

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It was no laughing matter, however, with reported heart attacks, other health conditions, and even deaths. Some say that the craze was caused by a "mass psychogenic illness," but there are no clear answers as to what definitively caused this weird occurrence.

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Reports of "dancing mania," taking place between the 14th and 17th centuries, have long puzzled historians and sociologists. A "dance epidemic" occurred in 1518 in Strasbourg, with around 400 people seeming to spontaneously dance and lose themselves.

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In the digital age, you expect to have every mystery solved and every question answered. Truth is, history is full of extraordinary events and occurrences which have remained unexplained for years. There have been disappearing islands, never-ending thunderstorms, and what could be a message from aliens.

Here's a selection of the most mind-blowing mysteries in history. Click on to examine the historical events that nobody can explain.