With the prevalence of murder mystery books and movies, there's no doubt that humans are fascinated by the idea of cracking a case. But some cases never get cracked.
Some of the most disturbing murder cases in history have never been solved and these bizarre crimes sometimes end up becoming part of popular culture as people try to make sense of what happened.
Some are committed by serial killers that terrorized communities for years. Others are shocking because of the way of the victims were discovered. And some stick in minds because of the victims' fame.
While there are countless murders that fit this criteria, these are a handful of the most notorious cases ever.
Scroll through to learn about them all.
The Zodiac Murders
One of the most notorious serial killers of all time was known as The Zodiac Killer. What's just as terrifying is that he was never caught.
The killer has been accused of the murders of at least five people in the late 1960s to early 1970s. Two more were confirmed to be attacked by the Zodiac. Four more murders/disappearances and one more unsuccessful abduction are suspected to have been committed by him.
To add to the terrifying mystique of the killer, he often wore a hood during his attacks and sent numerous coded letters to local newspapers about his crimes.prevnext
The Whitechapel Murders
Jack the Ripper's notorious crimes may never be solved, and that's one reason it's compelled amateur sleuths for more than a century.
There were 11 murders of young women in the Whitechapel neighborhood of London between April 1888 and February 1891, and at least 5 of them are confirmed to be by the man dubbed "Jack the Ripper." Some of the grisly murders involved organ removal, so a perpetrator with surgical knowledge was suspected but never caught.
Like in the Zodiac murders, letters were sent to local newspapers and attributed to the killer, but their authenticity has been disputed.prevnext
The Death of JonBenét Ramsey
In Dec. 1996, child beauty queen JonBenét Ramsey was found dead in her family's home at the age of 6.
She was killed by strangulation, and she was also struck in the head. A ransom note was found, but it soon became the basis for the conspiracy that one of the family members had killed Ramsey, either intentionally or accidentally.
That conspiracy has never been proved, and police work on the case has also been questioned. It received an incredible amount of media attention at the time and there are still new developments being found to this day.prevnext
The Black Dahlia Murder
Aspiring actress Elizabeth Short, known as the Black Dahlia, was found murdered on Jan. 15, 1947. What made her death go down as one of the most mysterious unsolved murders or all time was the condition of her body when she was found.
Her body was cut in two across the midsection. The halves were cleaned and posed with a 1 foot gap in between. Her blood had been drained, and her mouth has been cut to her ears.
Despite numerous investigations over the years, the perpetrator has never been caught.prevnext
The Murders of Tupac and Biggie
The deaths of hip-hop rivals Tupac Shakur and Christopher Wallace (a.k.a. Biggie Smalls) are the two of the most notorious music-related murders.
After attending a Mike Tyson fight in Las Vegas, the vehicle Shakur and Suge Knight were riding in were met with a hail of bullets from a white Cadillac on Sept. 7, 1996.
Shakur was struck four times, and later died at the hospital six days later. The murderers were never found, but conspiracies about the death have ran rampant in the two decades since.
Biggie, also known as the Notorious B.I.G., was suspected to be connected to the murders. He himself was gunned down on March 9, 1997, in a similar drive-by shooting.
It's unclear whether Biggie's murder was in retaliation to Shakur's, but the murderer was never caught.prevnext
Jack The Ripper Murders
Jack The Ripper remains one of the best-known unidentified serial killers in crime history. There are five murders from 1888 attributed to him, and his victims were usually female prostitutes working in London's East End slums. The previously mentioned Whitechapel Murders have also been linked to him.
After 1888, there were more murders believed to be connected, but police could not find evidence to prove it. The case has never been solved, although there are hundreds of theories and it has provided inspiration for countless movies, TV shows and books. The case files also provide an intricate look into how Victorian police investigated crimes.prevnext
The Murder of the Grimes Sisters
On Dec. 17, 1956, the Grimes sisters - 15-year-old Barbara and 13-year-old Patricia - left their house at 7:30 p.m. in Chicago to see Elvis Presley's Love Me Tender again. They never came home and by 2 a.m. the following morning, their family realized something happened. This launched a search of Chicago, and led to reports of them being seen outside Illinois. They were even allegedly seen in Nashville, which prompted the theory that they went to Nashville to meet Presely.
Their bodies were found on Jan. 22, 1957 in Willow Springs, Illinois. Their bodies were in odd positions, and both were nude. Police believed they were laying there for at least two weeks.
The crime was never officially solved. Charles Leroy Melquist was convicted of a similar killing of a teen girl in Illinois, but he was never officially connected to the Grimes case.
The Axeman of New Orleans Murders
The Axeman of New Orleans was linked to the murders of six people and the attacks of 12 others in 1919. Many of his victims were Italian or Italian-American. In March 1919, he terrorized New Orleans when he had a letter published in newspapers nationwide, claiming he would kill someone just after midnight on March 19, but would not kill anyone at a club where jazz played. He did not kill anyone that night. The Axeman mysteriously disappeared in October 1919.prevnext
The Servant Girl Annihilator Murders
The Servant Girl Annihilator is the name of an unknown serial killer who terrorized Austin, Texas in 1884 and 1885. The person killed seven women and one black man, and wounded six women and two men. According to one theory that originated in 1888 suggests the killer and Jack The Ripper were the same person.prevnext
The Feb. 9 Killer
The Feb. 9 Killer is a name given to an unknown serial killer linked to two murders in Salt Lake City on Feb. 9, 2006 and Feb. 9, 2008. Sonia Mejia, her unborn child and Damiana Castillo were killed by the same man. Although the murders of Mejia and Castillo happened two years apart, they were linked using DNA analysis. According to a 2013 Fox13 report, police think the suspect is Latino and was possibly a teenager at the time of the murders.prev