There are actually quite a few noteworthy ones, so I'll try to tell you 10 of the ones I consider the most disturbing, but it's impossible to put them in any particular order since each of these events resulted in the loss of one or more human lives:
1-Djatolv Pass:
The incident known as Dyatlov Pass occurred on February 1, 1958, and the tents of some hikers had been torn to pieces with a knife from outside, and the bodies of some of them were found a little further away with wounds on their bodies and with evident signs of terror on their faces. Even today it is not known who or what was the architect of the massacre and this makes the story even more disturbing, since many things remain inexplicable.
2-the Bluebeard of Gambeis:
Henry Desire Landru, known as the Bluebeard of Gambeis, was an alleged French serial killer who, according to investigators of the time, lured at least nine women to his home during the First World War through marriage proposals. He then strangled them, chopped them up with an axe, and burned them in the stove, all with the aim of robbing them of their belongings. He was sentenced to death and beheaded on February 25, 1922. Even today, it is unclear whether he was actually responsible for those murders.
3-The Murder of the Black Dahlia:
Elisabeth Short, known as the Black Dahlia, is one of the most enigmatic cases of the 20th century. Elisabeth (an aspiring actress with a complicated life) was brutally murdered on January 15, 1947. The killer disfigured her face, split her body in two, and drained it of blood. He then removed a piece of skin with a tattoo and placed a lock of hair in her vagina. The police were also called, but to this day no one knows who is responsible for that massacre.
4-the Fazio rocks incident:
It was a hot morning in 1930 in Rocchette di Fazio, Tuscany, and a young girl had gone to throw garbage off a cliff, but she never returned home. After a week of searching, the body was found in the woods surrounding Rocchette di Fazio. According to some, the girl had "for some reason" leaned over the cliff and fallen, dying instantly. Some also claim she was pushed by someone else, although this hypothesis has never been fully confirmed.
5-the Monster of Florence and his companions:
Between 1968 and 1985 in Florence, Tuscany, Italy one or more executioners mercilessly killed 8 couples, or 16 people. The killer killed the two boys with gunshots, then carried the girl's body out of the car and mutilated it. After a series of elaborate investigations, Mario Vanni, Giancarlo Lotti and Pietro Pacciani (the drinking buddies) were arrested, but even today, just like that of Henry Landru, their guilt is still doubtful.
6-Kata's disappearance:
On June 10, 2023 in Florence Mia Kataleya Chicclo Alvarez, known to all as Kata, aged 5, was playing with her brother and other children outside the hotel where she lived, and her uncle had gone into the house for a moment while her mother was at work and Kata, without any explanation, left the gate of the building and never returned. Almost a year after her disappearance, nothing has been known about the little girl's fate.
7-the murder of JonBenet Ramsey:
It was December 25, 1996 when 7-year-old JonBenet Ramsey was found dead in the basement of her home, with signs of physical and sexual abuse on her body. There were multiple suspects, but there was not enough evidence to convict anyone. On December 19, 2019, a convicted pedophile confessed to the murder and said it was a mistake, although today the truth has not fully emerged.
8-The Zodiac Killer:
The Zodiac killer also known as Zodiac was an American serial killer who at the end of 1960 in San Francisco, United States killed 5 people although according to the letters he sent to the media and to the police the victims were at least 25, Zodiac generally killed with gunshots or with stabbing weapons (knives), even today his identity is unknown despite numerous theories.
9-The Disappearance of Emanuela Orlandi:
It was June 22, 1983, when a Vatican citizen named Emanuela Orlandi disappeared in Rome. She was on her way to catch a bus with some of her friends when, according to witnesses, she got into a man's car and never returned home. The Orlandi case involved the Magliana gang, the Vatican, Enrico de Pedis, and even the theory of an alleged serial killer, given that a month later another girl named Mirella Gregori disappeared, yet to this day no one knows the truth.
10-Jack the Ripper:
Between the summer and fall of 1888, in Whitechapel, in London's East End, a man known as Jack the Ripper spread terror, killing five prostitutes and sending numerous letters to the police, signing himself as Jack the Ripper. The killer slit his victims' throats, then mutilated them and slit their bellies, before disappearing into thin air, and for this reason he is considered the most famous murderer in history.