Warning: Graphic content ahead, viewer discretion advised.
We recently asked the BuzzFeed Community to tell us what unsolved mystery keeps them up at night. Here are the bone-chilling results...
1. The disappearance of Bobby Dunbar who was "returned" to his family, but turned out to be another child.
3. The Yuba County Five who all had mild mental or psychiatric issues and mysteriously went missing.
4. The death of Rebecca Zahau who was found at her millionaire boyfriend's home.
5. The Black Dahlia whose murder in 1947 became highly publicized due to the graphic nature of what happened to her.
6. The case of Timmothy Pitzen who disappeared after his mother's body was found with a note saying Timmothy was OK and would never be found.
7. Australia's serial rapist, Mr. Cruel who has never been caught.
8. John Anglin, Clarence Anglin, and Frank Morris's disappearance from Alcatraz prison in 1962.
9. The Lane Bryant murders — the shooter still remains unknown.
10. Susy Tomassi an older woman with dementia who disappeared one day and has not been found.
11. The death of Gareth Williams, a British intelligence employee who was possibly assassinated.
12. The Sodder Children disappearance whose bodies were never found after a house fire.
13. The Dyatlov Pass incident where nine people died in the mountains of Russia under mysterious circumstances.
14. The death of JonBenét Ramsey, a 6-year-old child pageant queen in 1996.
15. The deaths of of Kris Kremers and Lisanne Froon who went on a hike in Panama and never returned.
16. The disappearance of Corrie McKeague, an RAF gunner who was last seen on CCTV.
17. The disappearance of Amy Lynn Bradley who went missing during a Caribbean cruise.
18. The Oakland County child killer case from the '70s that has had many suspects over the years, but is still an unsolved case.
19. The disappearance of Kyron Horman that sparked the largest criminal investigation in Oregon history.
20. The disappearance of Jesse Leopold who vanished without a trace just a few years ago.
21. Finally, the widely publicized Madeleine McCann case who went missing from her bed in 2007 while her family was on vacation in Portugal.
Submissions have been edited for length and/or clarity.