Mysteries
I'm fascinated by mysteries - questions unanswered and puzzles unsolved even though it seems that they should have been by now. The following is a list of interesting real-world mysteries, organized into rough categories and with a reference or two if you want to read further. I have also taken the liberty of marking a few of my favorites, these are a good starting point if you want to spend an evening feeling puzzled or frustrated that we don't know more.
Note that I am selective but somewhat arbitrary about what mysteries make the list. Some often mentioned mysteries, such as the Roanoke Colony, have generally well-accepted explanations and no compelling reason not to accept these explanations, so I ignore them. It is also quite impossible to list every unsolved burglary and murder, so I limit 'cold-case crime' mysteries to only those which are particularly, well, mysterious. Finally, although I absolutely love conspiracy theories, they're a topic for a different page, and so I only list a mystery if there is some compelling evidence that the mystery is actually real.
As for sourcing, I regret that I have none in most cases. I have been keeping this list, in various forms, for over ten years now, which for someone of my age is an incredibly long time to have been doing something. The old versions of it, and associated memory of where I found any of these, are now missing. Call that a mystery, if you'd like.
Murders and Ciphers
These types of mysteries are so common that they get their own category. In a “murder and cipher” mystery, a dead body is found, with foul play suspected, and on or around that body there are apparently encrypted notes.
Ricky McCormick (1999): McCormick, an occasional felon and borderline illiterate, is found dead in a corn field. Many years later, investigators release to the public that he was carrying two pages of apparently enciphered notes. The ciphers remain unsolved. WP
Lead Masks Murder (1966): Two dead bodies are found in Brazil, each with a lead eye-mask. They have with them a notebook containing rather mysterious instructions about waiting for the “mask signal”. The case remains unsolved. WP
Unsolved Murders and Disappearances
There's any number of unsolved murders out there, but a few of them were so strange that they deserve mystery status.
Bear Brook Murders (1985, 2000): In New Hampshire's Bear Brook State Park, a hunter stumbles upon two dead bodies hidden in a metal drum in 1985. Fifteen years later, a second drum is found nearby, containing two more bodies, apparently killed at the same time as the first two. DNA analysis determined them to likely be a family, of a mother and three children. While it's a good enough mystery why other metal drums in the immediate area weren't checked after the first was found to contain murder victims in '85, the murder case as a whole remains stubbornly devoid of leads. WP
Sodder Fire (1945): A house in Fayetteville burned down, and five child residents went missing. Tragic, but not so mysterious, even when the parents apparently irrationally believed that the five children had survived. However, the saga went on almost to the present day, with the parents occasionally turning up bits of evidence supporting their theory (like an anonymously sent photograph possibly showing one of their children as an adult) and even a disappearing private investigator. This case strikes me as an early version of the Kyron Horman case. WP.
Amelia Earhart (1937): It's well-known that Amelia Earhart and her navigator, Fred Noonan, disappeared in the Pacific ocean while flying one of the last legs of her trip all the way around the world. The mystery, here, is what exactly happened to them. The mainstream consensus, backed by the Navy, is that they went down in the Pacific Ocean - this is quite likely, but impossible to prove because the evidence is now far below the sea. That leaves room for a vocal minority to promote other theories, backed by some loose evidence including apparent radio transmissions received after their presumed crash date. A historic plane recovery organization has set their sights on a particular island they think Earhart and Noonan may have been marooned on, but decades of attempts have produced virtually no evidence. WP Article.
Unsolved Crimes
D B Cooper (1971): In a mystery rather famous in my pacific northwest home, D B Cooper (pseudonym) hijacked an airplane, ransomed it for money, and then after a landing in Seattle to pick up the cash ordered the pilots to fly south and actually jumped out of the back of the aircraft with a parachute. Neither D B Cooper nor almost any evidence have been found, although a small amount of money did turn up in the woods. WP, recent article on new evidence
Serial Killers
It's difficult to get away with murder, and it's even more difficult to get away with it a bunch of times. A few notable people have pulled it off, though.
West Mesa Killer (2001-2005): Here's some local flavor. The West Mesa Killer refers to the murderer of 11 women found in 2009 on the (at the time) sparsely populated West Mesa of Albuquerque. Albuquerque PD continues to work the case, and seems to have accumulated various bits of additional evidence in recent years, but it remains unsolved. Recently, the frontier of new housing development construction on the West Mesa has reached the site the bodies were found, driving renewed attention to the case including a series of billboards appealing for information. WP
Long Island (1996-present): This serial killer has claimed as many as 18 victims, possibly including several extremely recent cases. The victims are generally sex workers. WP
Tylenol Murders (1982): Medication bottles are now fitted with tamper-evident seals because of this incident, in which seven people died from cyanide added to Tylenol pills before sale. There have been suspects (including Ted Kaczynski), but the case remains unsolved. I personally suspect that the tampering occurred in the factory rather than in stores, as a former Johnson and Johnson employee suggested in 2011. WP
Brabant Gang (1982-1985): This group of three people with various others assisting terrorized the nation of Belgium for several years, conducting brazen robberies and often killing in the process. Despite killing 28, they've never been caught, perhaps in part because of complicit police. The case is wrapped up in several events of Belgian politics and helped lead to national police reforms. WP
Highway of Tears (1969-2011): Although not clearly the work of a serial killer, a stretch of British Columbia's highway 16 has seen an unreasonable number of murdered and disappearing women - about 20, depending on your criteria for inclusion. One case was solved, and serial killer Bobby Jack Fowler is suspected in others, but despite a major investigative project by the RCMP it remains unclear if the cases are even related. WP
Science
The Moon Illusion: The moon appears larger when near the horizon. This phenomena has had proposed explanations from all kinds of branches of science but continues to frustrate, as none of them quite fit what people clearly see when they look at the sky. The perception is almost certainly psychological, but attempts to produce a similar illusion in the lab have failed. article, WP
Major Events
9/11
9/11 has produced almost unlimited conspiracy theories. Here, I include a number of questions that seem to be actual mysteries - that is, there are questions beyond just accusations of conspiracy.
Sneha Anne Philip: This physician disappeared at around the time of the 9/11 attacks. Because she was a doctor and in the area, she's assumed to have perished while trying to assist 9/11 victims (and a court ultimately officially ruled this to be the case), but investigations after the fact revealed a complex double life and a number of other possible causes of her death. WP
Anthrax letters: There is limited evidence suggesting that the anthrax letters sent at around the same time as the attacks may have been the work of the same terrorists, although it's not clear why exactly. The FBI accused an unrelated biologist, but there are questions about the validity of that accusation. article, article
And, just for good measure, a short list of particularly interesting conspiracy theories related to 9/11. Generally, these are conspiracy theories without any strong evidence.
- WTC 7: WTC building 7 collapsed after the two towers, apparently as a result of direct damage from falling debris and a long-burning fire. Some people insist the damage was only superficial, though, and the building must have been intentionally demolished.
- Flight 93: It is a popular theory that Flight 93 was actually shot down on the orders of Dick Cheney, and the passengers fighting back was either coincidental or a cover story developed after the fact. There are some statements from officials that lend credence to this idea, but to be quite honest they appear to just be the result of officials speculating where they shouldn't.
- Explosions from below: Survivors in the lobby of one WTC building report hearing explosions from below them, rather than above. This is probably just a result of confusion and poor memory resulting from such a crisis, but some maintain that it is evidence of explosive demolition.
World War II
There are several different layers of reasons that WWII produced a variety of mystiers. Of course, it was an event of large-scale global significance, so historians have devoted a great deal of time and effort to the war. There was a significant element of intelligence and counter-intelligence, resulting in rampant rumors flying during combat. And perhaps most interestingly, the Nazis intentionally destroyed evidence of their exact activities, particularly Operation Reinhardt (the well-known mass extermination program for Jews at three death camps), leaving manyquestions about the particulars of the holocaust.
- Die Glocke: Die Glocke, or “The Bell,” was reportedly the codename for a secret research project near the end of WWII. This information came largely from a single source and so may be completely fabricated, although there is some light circumstantial evidence validating an actual project. The nature of the project is unknown and theories are often quite conspiratorial, ranging from nuclear weapons to a time machine. It remains unclear if Die Glocke was ever real and, if so, what exactly it was. WP
- Nazi Gold Trains: The Nazis seized a huge amount of valuables, primarily gold, from various populations that they subjugated. Much of this was transported by train to evade the approaching allied forces near the end of the war, and it's widely believed that in some cases those trains were hidden away in tunnels. The best-known case is in Poland, where several explorers claim to have located the train, so perhaps there will be some resolution to this mystery soon. WP
- The Amber Room: The Amber Room was a Russian national treasure, an incredibly intricate set of wall panels and decorations originally produced for a lavish palace. The Nazis looted the Amber Room and transported it to Konigsburg, its whereabouts after that point remain a mystery. It is a distinct possibility that it was destroyed as collateral damage of allied bombing operations, although there is also some evidence that it may have been moved out of Konigsburg and hidden. WP