Uncertainty and mystery have always plagued human speculation in a very fearful, yet intriguing manner. While there may be actual scientific explanations and rational causes for all mysteries, it is very difficult to find reasonable evidence and solve some very strange events. The world has seen several strange occurrences that still remain a mystery to this day. Be it a missing aircraft, a disappeared person, or unsolved and bizarre murders, these chilling incidents plague us forever with how mysterious they are. Here are ten of those mysteries that remain unsolved to this day.

1 The Disappearance of Madeleine McCann

Madeleine Beth McCann was a three-year-old girl who disappeared mysteriously from her bed at a resort in Praia da Luz, Algarve, Portugal on 3 May 2007. She was on a vacation in Portugal with her parents, twin siblings, and a group of friends and family. She has never been found despite several investigations.

Madeleine McCann was left in a ground-floor apartment room by her parents to sleep along with her twin siblings. The parents and their friends were dining in a tapas restaurant 55 meters away from the room. At around 10 p.m., her mother Kate realized Madeleine was missing. 

Eventually, this case would go on to be one of the most popular media-covered cases ever. Several investigations opened up, including a DNA mishap that wrongly accused Madeleine’s parents of being the culprits. Furthermore, there were sightings on the same day by people of a man carrying a child. One sighting was reported by Jane Tanner, a friend of Kate’s.

The other, which was considered the actual criminal by many, was sighted by an Irish couple. Dubbed the “Smith sighting,” Martin and Mary Smith saw a man carrying a three- or four-year-old girl around the same time frame as Madeleine’s disappearance. However, the case has never been solved due to a lack of proper evidence. (1, 2, 3)

2 The Identity of the Zodiac Killer

The Zodiac Killer is one of the most popular cultural criminal icons, infamous for killing a lot of people and sending coded letters to newspapers threatening to kill more people unless they published them. He operated in the northern parts of California in the 1960s, and although there have been several suspects, a complete match was never obtained due to lack of evidence.

The Zodiac Killer is assumed to have started his killing spree on 20 December 1968 when he shot and killed a couple on Lake Herman Road, in Benicia, California. He then tried to kill another couple in Vallejo, only four miles away from the Lake Herman murder site, at midnight, on 4 July 1969 in the Blue Rock Springs Park, Vallejo.

One of the victims, Michael Mageau, survived the attack. At around 12:40 a.m. on 5 July 1969, a man called the Vallejo Police department claiming to be the killer. He also claimed that he killed the two other victims on Lake Herman Road around six months earlier.

Later, on 1 August 1969, the killer reportedly sent three letters to the Vallejo Times-Herald, San Francisco Chronicle, and the San Francisco Examiner asking them to publish them.

He would eventually go on trying to kill three more people of which one would survive. He stabbed a couple at Lake Berryessa on 27 September 1969 and later killed a taxi driver in Presidio Heights on 11 October 1969.

Several other attacks and murders have been attributed to the Zodiac Killer, but none have been verified. Several suspects including Arthur Leigh Allen, whom many suspected of being the Zodiac, were interrogated but never charged. (1, 2, 3)

3 The Disappearance of Jimmy Hoffa

Jimmy Hoffa was a popular American Labor Union leader and was the president of the International Brotherhood of Teamsters from 1957 to 1971. He disappeared on July 30, 1975, under mysterious circumstances in Bloomfield Township, Michigan, USA, and was later declared dead on July 30, 1982. His body was never found.

Jimmy Hoffa was under tremendous pressure and had already received threats from people like Anthony Provenzano who opposed Hoffa’s rise to power. On the day of Hoffa’s disappearance, he was supposed to meet with Provenzano and Anthony Giacalone at 2:00 p.m. at the Machus Red Fox Restaurant in Bloomfield Township, Detroit.

Hoffa left his house at 1:15 p.m. and had later called his wife around 2:30 p.m., annoyed that he was being stood up by the people he was supposed to meet. Several witnesses saw Hoffa pacing around his car, and it is reported that he left with three men in a maroon car without a struggle around 2:45 – 2:50 p.m.

He was not seen after that, and several theories about his disappearance and murder have surfaced, all lacking proper evidence. It was also made into a movie called The Irishman in which Hoffa is shown as being killed by Frank Sheeran, a hitman. (1, 2, 3)

4 The Disappearance of Andrew Gosden

Andrew Gosden was a 14-year-old boy from Doncaster, South Yorkshire. On 14 September 2007, he reportedly withdrew 200 GBP from his bank account and was last seen on surveillance footage leaving the King’s Cross Station. It was later found that he had bought a one-way ticket to London.

Andrew Gosden was reportedly a gifted student at his school and kept to himself most of the time. On the day he went missing, it is said that he exhibited slightly strange behavior as he woke up late and was irritated. He then changed his usual routine, walked to a cash machine in a nearby garage, and withdrew almost all of the money in his bank account, 200 GBP.

He then went back home, put his school clothes in the washing machine, changed to casual wear, a black t-shirt featuring the metal band Slipknot, and black jeans. He then went to the Doncaster train station and purchased a one-way ticket to London. He boarded the train alone to King’s Cross Station, London at 9:35 a.m.

A passenger in the train who reportedly sat next to him remembers that he seemed alright and was too engrossed in his video game console. The train arrived at King’s Cross Station at 11:20 a.m.

At 11:25 a.m., he was captured by surveillance cameras leaving the main entrance of the train station, which happened to be his last sighting. He has never been found to this day, and his parents have still not changed the locks of their house in case he returns. (1, 2, 3)

5 The Annecy Shootings

The Annecy Shootings, also known as the French Alps Shootings, was a barbaric incident that occurred on 5 September 2012 near the southern end of Lake Annecy. Three members of a family from Britain and a French Cyclist were found murdered near Chevaline, Haute-Savoie. Authorities have still been unable to point out the exact cause or reasons behind this attack.

Out of the four people killed in the Annecy Shootings, three were related. An Iraqi-born British tourist named Saad-al Hilli, his wife Iqbal, and her mother Suhailla al-Allaf were the three related people killed in this attack. A French cyclist named Sylvain Mollier was also killed in this incident but apparently was not connected to the other three.

The two daughters of the al-Hillis escaped this ordeal alive. The elder daughter, Zainab, was aged seven and survived a bullet wound in her shoulder and another head wound. The other daughter, aged four, reportedly was hidden under the legs of her mother’s body.

There have been several suspects associated with this case, and speculations of nuclear secrets from hitmen to psychopathic killers, but none of these theories have come up with any convincing evidence. (1, 2, 3)