10 Unsettling Incidents We Still Can’t Explain

When something strange happens, we try to make sense of things by putting the scattered puzzle pieces together. For example, when Flight MH370 dropped off the radar in 2014, most people eventually accepted the theory that the pilot was suicidal.

But how do we know that for a fact? The reality is that no one knows what happened that day except those on the plane. And the only thing we do know is that they are all dead because a few pieces of the plane have been found. There is nothing else we can know for sure until the rest of the aircraft or bodies are found.

The same applies to most other mysteries. Strange and unsettling things happen all the time. Without finding undeniable evidence, we have no choice but to wait and wonder what really happened.

Related: 10 Unsolved American Mysteries

10 What Is Behind the Outer Hebrides Hum?

The Outer Hebrides have been inhabited for around 4,000 years. Today, these islands span roughly 130 miles (209 km) and are home to approximately 28,000 people.

The islanders love living in this gorgeous setting, except when a low-frequency humming sound sours their days and nights. Around 200 people continue to hear the so-called Hebridean Hum, which prevents them from sleeping properly. The 200 islanders reside on the Isle of Lewis, and many have tried to figure out the source of this annoying hum. The hum has been recorded at 50 Hz and seems strongest on the east coast.

Some Lewis residents have complained that they cannot focus on anything besides the humming sound, while others have reported fluttering sounds in their ears, dizziness, and headaches. In April 2025, a senior educator who set up a Facebook support page for those plagued by the hum confirmed that the hum is becoming louder, more constant, and intrusive. Many residents are becoming increasingly distressed by it; some even feel completely isolated when they hear it.
As it usually happens, theories about what could be causing the hum quickly turned dark. While some believe the sound may come from a local sewing plant, others think a mystery submarine might be operating nearby. One person even likened the sound to hearing the Earth turning.

At the time of this writing, more theories, including idling cargo ship engines and power stations, have been put forward, but no theory has yet been proven correct.^[1]

9 What Caused the Denmark Tremors?

On May 13, 2023, dozens of people living on the island of Bornholm in Denmark reported experiencing strong tremors. This prompted a seismological investigation, which revealed that no earthquake had occurred.

If it’s not a persistent hum freaking people out on islands, it’s unexplained tremors. On May 13, 2023, dozens of people living on the island of Bornholm in Denmark reported experiencing strong tremors. This prompted a seismological investigation that revealed no earthquake occurred.

The tremors happened around 20 minutes after a small blast in Poland, but scientists were not convinced that was the cause. On the same day and night, there were more reports, around ten of them, about tremors in southern Sweden (the part that is north of Bornholm). Some experts believed that atmospheric pressure waves caused the tremors, but they were unable to determine what had caused them.

Sometimes, strange tremors, rumblings, and seismic waves go pretty much unnoticed, like the event on November 11, 2018. Several seismic waves rippled worldwide just before 9.30 am on that particular Sunday. This went on for 20 minutes, apparently emanating from an area 15 miles (24 km) from the Mayotte shore.

The waves extended across Africa and the Atlantic, eventually reaching Hawaii. Despite this massive range, no one felt them. Only one person on Twitter, monitoring the U.S. Geological Survey’s seismogram live stream, picked up an unusual signal.

Experts called the “zigzag” waves too perfect to come from a natural source. Which means they still have no idea what caused it.^[2]

8 What Happened to the Mako Cuddy Cabin Boat?

Around New Year’s 2020-2021, a blue and white 29-foot (8.8-m) Mako Cuddy Cabin boat with 20 passengers left Bimini and headed towards Lake Worth Beach, Florida. The boat was reported missing on January 1, 2021, and it is believed that something went wrong in the Bermuda Triangle section of the waters between the Bahamas and Florida.

A search was launched immediately, and more than 17,000 square miles (44,030 square kilometers) were covered in 84 hours. When the search was eventually called off, the Coast Guard confirmed they found no clues to tell rescuers what may have happened to the boat.

The Bermuda Triangle part of this incident is not nearly the strangest. The names of those onboard were never publicly released. There is no further information remotely related to this incident except for another strange incident that occurred six months later.

On June 24, 2021, a boat was discovered drifting near the coast of Turks and Caicos. The boat had 20 dead people onboard. The fisherman who spotted the boat alerted the police, who towed the boat ashore. The police ruled out foul play, stating the boat was not local and was not meant to be anywhere near Turks and Caicos. Weirdly enough, no names were released either.

As of May 2025, there is no official explanation for either of these incidents.^[3]

7 How Safe Is AI Technology?

Artificial intelligence (AI) has been around for a while, and most people are thoroughly impressed with this technology. Those who can afford it are even considering having AI robots run their household, so to speak. However, a video that went viral on social media at the beginning of May 2025 may force some to think twice. The clip shows CCTV footage recorded at an unnamed factory in China.

In the footage, two workers are in the process of activating an AI humanoid robot hanging from a small crane. The robot then abruptly comes to life, flailing its arms around, seemingly to attack the workers. It also knocked over a nearby computer in its quest to apparently hit the two men. The men struggle to get the robot under control, and it is only subdued when one of the workers sneaks behind it and pulls its stand back.

It is unclear what caused this “tantrum,” and the footage is truly disturbing. Robot manufacturer Nvidia tried to downplay the incident, stating these robots were meant to work alongside humans to increase productivity. They can load boxes and assist with customer service.

At the same time, however, Nvidia also said that the robots have “degrees of freedom.” Therefore, it is crucial to monitor the algorithms that humanoids rely on to avoid new risks and misinterpretations.^[4]

6 What Are Those Trumpet Sounds That Emanate from the Sky?

If you regularly scroll through social media, chances are you’ve seen a video of skyquakes or sky trumpets. Some of these sounds are horror-movie frightening, while others can be likened to a loud bang (similar to artillery) or even a horn.

Skyquakes tend to happen in areas close to lakes, oceans, rivers, etc. Reports of this phenomenon have been reported from all over the globe, including India, Argentina, Canada, the United States, and Japan.

The first skyquake was recorded in New Madrid, Missouri, when locals reported hearing the sound of artillery before and during a 7.2-magnitude earthquake. These ‘quakes’ seem to sound different in various parts of the world, with New Yorkers once referring to them as Seneca Guns and the Japanese calling them “uminari,” which means “cries from the sea.”

Scientists have tried to solve the mystery of sky trumpets over the years and, as such, have come up with several theories. These include air pressure changes, lake gas, airplanes, or seismic activities. But there is no definitive answer as yet.^[5]

5 What Really Happened to the Eight-Day Bride?

Some mysteries are much closer to home than elusive sounds from the sky. But that doesn’t mean they’re any easier to solve.

On May 12, 1947, a 22-year-old woman named Christina eloped with her boyfriend, 26-year-old Jack Kettlewell, against her parents’ wishes. Jack and Christina decided to honeymoon in a remote cabin in Severn Falls, Ontario, Canada. Jack’s friend, Ronald Barrie, owned the cabin and soon decided to join them there.

As reported later, the three of them spent a lot of time together before Christina was found dead a mere eight days later. The cabin had also been burned to the ground. Jack and Ronald escaped the fire, but Christina was discovered lying face down in a 9-inch pool of river water, only a few meters from the remains of the cabin. Her cause of death was determined to be drowning. As Christina was tragically only a newlywed for eight days, she was nicknamed the eight-day bride. And the eight-day bride’s death was considered suspicious.

First, there was no smoke in her lungs and no burns on her body. This is strange since she was wearing the pajamas she had on the night the cabin burned down, which means she had to have been inside it. If she had been inside when the fire started, there should have been at least a trace of smoke in her lungs.

A subsequent investigation revealed that Barrie was the beneficiary of two $5,000 life insurance policies owned by Jack and Christina. The provisions of these policies included double indemnity, meaning Barrie would get twice the amount if Jack and Christina died in an accident.

It was also suggested that Jack and Barrie were lovers and planned to get rid of Christina. Jack was allegedly forced into admitting that he had an affair with Barrie. Furthermore, it was revealed that Christina once tried to kill herself with poison. She tried again to end her and Jack’s lives on another occasion, according to a string of suicide notes.

It has been 78 years, and the full truth remains to be discovered, as no one has ever been officially charged or tried. Did Christina’s husband murder her? Did Barrie? Or did she kill herself? We may never know for sure.^[6]

4 What Happened in the Woods House?

You can’t write a list like this and not include at least one paranormal mystery. While most people immediately write off all things spooky and supernatural, Ed and Mary Woods couldn’t do the same when they moved into their new Washington home in 1994.

Everything went great for seven months, and then weird things happened. Mary began hearing the sound of a music box playing day and night. When it didn’t stop, she tried to follow the sound and decided it could only come from Ed’s office inside the house.

But, even after searching the entire office, she found nothing resembling a music box. Ed was also freaked out by his office after he heard the doorknob jiggle while the door was closed. When he opened the door, no one was on the other side. He checked the rest of the house, only to find Mary and their two daughters fast asleep. Ed was so rattled by this incident that Mary contacted a seismologist. The seismologist confirmed there was no seismic activity that could have caused the doorknob to jiggle.

Things progressively got worse to the point where Mary saw the ghost of a woman in a flannel nightgown with a scarf around her head. After conducting some research, Mary discovered that the ghost resembled the previous resident, who had died of cancer.

Ed saw a man with a mustache standing in the living room wearing a ribbon tie. Ed and Mary saw a young girl who giggled loudly whenever they spotted her. Objects also began floating throughout the house. After a ghost expert, Loyd Auerbach, investigated the Woods’ house, he confirmed that he had found a lot of electromagnetic pollution and that he could find no reasonable (natural) explanation for what the Woods had experienced.

The Woods’ house haunting became an Unsolved Mysteries episode, and Larry King also interviewed the couple. And, there is still no explanation for what happened in their home.^[7]

3 Who Sabotaged the City of San Francisco Train?

Chilling incidents are not confined to ghostly figures or unexplained deaths, either. Sometimes, someone (or more than one person) has a vendetta against another person or institution. Or, they simply have an urge to kill. This usually ends in tragedy, which is exactly what happened on August 12, 1939. On this day, the City of San Francisco Train was en route to Oakland, half an hour behind schedule. The engineer, Ed Hecox, increased the speed to 90 mph to make up for some of the lost time.

Unfortunately, there was nothing Hecox could do about the rail patch near Harney, Nevada, that had been moved out of alignment with the rest of the track. When the train hit it, it derailed, killing 24 passengers and injuring a further 121 (including crew members). Hecox miraculously survived and called emergency services after running to Harney to find a telephone.

As the days unfolded after the derailment, divers found tools in the Humboldt River. This proved that the tragedy was caused by sabotage. A bounty of $10,000 was set up to catch those responsible. But nothing came of this effort.

The media was unsympathetic, accusing the Southern Pacific Railroad (one of three railroad companies operating the City of San Francisco Train) of fabricating the sabotage story. They believed the company wanted to hide negligence after allowing the engineer to increase the speed. However, the company stuck to its guns, as did the FBI, which claimed that the rails had been intentionally misaligned.

In 1995, another train derailment occurred in Arizona. Authorities found similarities with the City of San Francisco train derailment, including tracks moved on a bridge with a high embankment and track circuits that had been bypassed. Still, this made no difference as the City of San Francisco wreck remains a mystery, as the perpetrators were never found.^[8]

2 Why Do People Keep Disappearing from Antigua?

People go missing every day. Some are found quickly. Others are never seen or heard from again. Sometimes, they disappear in big cities. Other times, they vanish from tiny islands. On the island of Antigua, which is just over 100 square miles (259 square kilometers), several people have gone missing over the last two years. And whereas other small islands eventually find bodies washed up on the shore or buried somewhere, those who disappear from Antigua are simply “gone.”

No one has come up with a reasonable explanation for why so many people go missing here. Over the last 24 months, nine have disappeared, including 74-year-old Hyacinth Gage. Hyacinth left her home six years ago to visit a doctor and never returned. A search party scoured the entire island, but Hyacinth remains missing. The only thing Hyacinth’s daughter knows for sure is that her mother handed her bag to a patient at the hospital. But she never came back for it.

Additionally, Hycinth’s daughter confirmed that local police became angry at volunteers searching for her missing mother and told them to stop. It is no wonder, then, that there are so many dark theories about these disappearances. Some residents believe the police simply lack the will to investigate, while others think that gangs or organ trafficking are to blame.

When 12-year-old Chantel Crump went missing on March 12, 2025, these theories went into overdrive. And they exploded when her body was discovered two days later. A woman has been arrested and charged with the girl’s murder.

As for those who remain missing, there are no answers yet. The list stands at nearly 60 missing people.^[9]

1 Who (or What) Killed Teketeke Gqontsi and Sandile Sibiya?

On October 5, 2017, 61-year-old Teketeke Gqontsi was admitted to a hospital in Stellenbosch in the Western Cape province of South Africa. He underwent abdominal surgery and was unable to walk directly afterward. A nurse attending to Teketeke left him alone for a few minutes to get clean linen. When she returned to his room, he was gone.

It took 13 days for hospital staff to discover Teketeke’s body inside the ceiling in an isolated area of the hospital. During the time he was missing, his family even received a phone call from a hospital staff member asking them if Teketeke had gone home.

An autopsy was done on Teketeke’s body shortly after he was found, and it stated that he died of natural causes. But how did he end up inside the ceiling? His family still doesn’t know.

On May 10, 2019, 53-year-old Sandile Sibiya broke his femur and was rushed to a Durban hospital in South Africa’s KwaZulu-Natal province. Sandile was due to be transferred to Addington Hospital after initial treatment, but when a nurse checked on him, he was gone. Staff searched everywhere for Sandile and then reported him missing to the local police. He was missing for two weeks when staff noticed a horrible stench and a leak coming from a storeroom inside the hospital. Sandile’s decomposing body was discovered in the storeroom ceiling on May 25.

Considering that Sandile had a broken femur, he would not have been able to walk, much the same as Teketeke. So, how did he end up inside the ceiling? Investigations revealed very little information, and both men’s families are still waiting for answers about these horrific incidents.^[10]