1. During the Renaissance, Cangrande della Scala, a well-liked Italian nobleman, became the ruler of Verona. However, his reign was short-lived. In 1329, shortly after taking control of a newly conquered city, he fell ill and died unexpectedly, allegedly from consuming contaminated water.

While many suspected foul play, it wasn't until 2014 that researchers conducted an autopsy confirming the rumors. The findings revealed that there was a significant amount of foxglove in his body, indicating intentional poisoning. It took 700 years to finally solve the mystery of his death.

2.  In 1932, in the neighborhood of Atlas in Stockholm, a 32-year-old sex worker named Lilly Lindström was discovered dead in her apartment in one of the most bizarre murders in Swedish history. The last person to see her alive was her friend and neighbor Minnie Jansson, who became concerned after not hearing from Lindström for several days and called the police. Lindström had been brutally beaten to death, and shockingly, her body had also been drained of blood. Upon finding blood on a ladle and an excessive amount of saliva at the crime scene, police speculated that the killer may have consumed her blood, leading to the nickname "Atlas Vampire." Despite their efforts, the murderer was never identified or apprehended.

3. In 1937, a young Italian woman named Laetitia Nourrissat Toureaux boarded a first-class carriage bound for Paris. She was alone when the train departed, but when it arrived at the next station just a minute later, six passengers entered the carriage to find Toureaux slumped forward with a dagger in her neck. She passed away before reaching the hospital, and the police were unable to locate any witnesses to the crime. It was later revealed during the investigation that Toureaux was an informant for a private detective agency, and it is believed that her work infiltrating right-wing extremist groups may have led to her tragic death.

4.  In 1934, an Austrian woman named Eloise Wehrborn de Wagner-Bosquet, also known as "The Baroness," came to Floreana Island with three men (two lovers and a servant) with the intention of constructing a luxury resort. This idea did not sit well with the existing proto-hippie ex-patriots on the island. As tensions escalated over the course of several months, Wehrborn de Wagner-Bosquet disappeared, along with one of her lovers.

5. British mountaineers George Mallory and Andrew "Sandy" Irvine died while attempting to climb Mount Everest in 1924. The mystery lies in how they died, as they were last seen just a few hundred yards from the summit on June 9 before disappearing entirely. Mallory's body was officially found in 1999, but without a camera or witnesses, it remains unknown if they reached the summit before their deaths. Irvine's body has never been recovered.