10 Creepy Science Mysteries That No One Can Explain

Welcome to WatchMojo, where well be covering the most haunting issues rooted in science, with many of them remaining unsolved.

#10: Nazca Lines

If youre flying over the Nazca Desert in Peru, you might catch a glimpse of these monumental lines carved across the landscape. We believe they were created between 500 BC and 500 AD. The lines join together to create incredible images, but they can only be seen from the air. It doesnt take a historian to realize we had no way of flying until centuries after their creation. The desert climate has preserved them wonderfully, allowing researchers to catalog and study them. Unfortunately, no one has any concrete idea why they exist. A recent theory from 2025 claims they were used for teaching lessons, with them being placed alongside pilgrimage routes. Instead of writing, they may have taught using the landscape.

#9: The L-8 Ghost Blimp

The blimp's popularity took a huge hit because of the Hindenburg disaster in 1937. Still, once the United States joined World War Two, the Navy kept a few blimps on hand. In August 1942, only a few months after Pearl Harbor, an abandoned blimp, the L-8, mysteriously appeared over San Francisco. It eventually crashed in Daly City, where they found no traces of its crew. It had departed from Treasure Island earlier that day, with two crew on board. Searches couldnt find any trace of them. The gondola was left in good condition, which indicated they didnt plan to vanish, spurring theories that they fell out by accident. To this day, no one has any confirmed theories, and we likely never will.

#8: The Afterlife

What happens after we die? Your guess is as good as anyone elses, since its a concept likely impossible to test. Weve developed tons of wildly different theories, from reincarnation to infinite paradise, but we cant agree on what happens. What about science? Can that solve the problem? Currently, not really. Researchers have extensively analyzed near-death instances, searching for trends and similarities. Most of them involve out-of-body experiences and people traveling towards a light. Some even claim they saw dead relatives. Disappointingly, theres no concrete way to prove what happens, so for now, the rare firsthand account is the closest we can get.

#7: Yonaguni Monument

The idea of Atlantis, a city lost to the sea, is usually considered science fiction. Well, off the coast of Japan, a real-life Atlantis may exist. Deep in the Pacific Ocean lies the Yonaguni Monument. It was discovered in 1986 by a diver, who found a stunning rock formation that looks man-made. Some marine geologists think theyre monoliths, created by people. A lot of people deny this idea, with the local government refusing to recognize them as significant. Quite a few geologists claim natural processes would be capable of making the formation. Similar structures exist in other places, all naturally made. Despite this, there are a few dedicated individuals convinced its the remains of an ancient civilization.

#6: The Pioneer Anomaly

In the early 1970s, NASA launched spacecraft Pioneer 10 and 11. They were the first objects to observe Jupiter and Saturn up close. They both launched with highly sophisticated tracking technology, which revealed they werent behaving as predicted. Both crafts slowed down unexpectedly, puzzling NASA, which initially had no clue what it was. One prominent theory was that an unknown force was responsible, potentially coming from a hidden planet, or even aliens. In 2012, they figured out that the suns light induced an asymmetric temperature gradient. This causes a backward pressure, thus slowing it down. Scientists agreed this was a solid explanation; therefore, it has since been considered solved.

#5: Honduran Fish Rain

The idea of it raining fish might seem like fiction, but in Yoro, Honduras, it happens as often as four times annually. Theyve had festivals to celebrate it since 1998, but its been happening way longer than that, since at least the 1800s. The most common scientific explanations are that its caused by tornadoes and waterspouts. These meteorological solutions all assert that the fish are sucked up into the air, then thrown across the region. The theory breaks down when you learn that the Atlantic Ocean, a probable fish source, is 45 miles away. So its unlikely theyd be carried from there, then dropped on a tiny town inland. Hence, it remains largely unexplained.

#4: The Dancing Plague

People love to dance, but its rare to see a whole village dancing. Its even rarer for them to dance constantly for weeks, with some dying of exhaustion. Rare, but not impossible, as proven by the infamous 1518 dancing plague of Strasbourg, in the Holy Roman Empire. It started with one woman, then spread to most of the village. It eventually stopped after dancers were taken to a shrine, with prayer ending the craze. The most accepted theory is that it was mass psychosis, caused by immense stress. The citizens had recently experienced war, famine, and numerous diseases, major contributors to the phenomenon.

#3: Sleep Paralysis

Now and again, you may wake up in the middle of the night, unable to move. You can hear and see, but youre physically paralyzed. This may even be accompanied by haunting hallucinations, which many compare to a demonic presence. This is the terrifying phenomenon of sleep paralysis. Even though its relatively short, its frightening. The specific cause is unclear, but we have a mild understanding of it. It happens when you become conscious during REM sleep, but your body remains paralyzed. Things we dont understand include what makes people more susceptible, alongside why some people have terrifying hallucinations but others dont. So its not a total mystery, but the details are still under investigation.

#2: The Wow! Signal

In 1997, a mysterious radio signal was detected by the Big Ear telescope, at Ohio State University. It was discovered by Jerry R. Ehman, who was so amazed he wrote wow! on the printout, giving the signal its name. It came from Sagittarius, lasting 72 seconds in total. Weve been unable to detect it since. Many consider it to be an alien signal, including Ehman himself. One team claims a comet caused the signal, but astronomers didnt agree, since the telescope wasnt pointed at one. In 2024, another report said a rare space event was responsible. It could also just be a human signal, but we have no clue what.

#1: The Fermi Paradox & the Great Filter

Since there are billions of stars similar to the sun, even with a low probability of life, the galaxy should be teeming with aliens. So why, apparently, isnt it? This is the Fermi Paradox. On its own, its not scary, but a proposed solution, the Great Filter, is harrowing. It says theres a huge obstacle stopping life from colonizing the stars. Its unclear if humans have overcome it. If its behind us, then humans have a bright future to look forward to. If its ahead of us, then were doomed. Either way, both are terrifying, and if the filter exists, then we may genuinely be entirely alone.

What mystery keeps you awake at night the most? Let us know in the comments below!