Sometimes, the universe decides to troll the whole human race and create something that simply cannot be explained.
As if to remind us we're not really in charge, that all our precious science and logic aren't enough to explain it all, homo sapiens is confronted with something so baffling the only recourse is to shrug and say 'it's a mystery'.
Some such mysteries are perfect storms of circumstances just right to create an end result that both fascinates and bamboozles. Others are deliberate obfuscations by someone trying to cover their tracks and hide the truth.
More than one could conceivably be deliberate fakes created solely to cause everyone to scratch their heads and make up stuff about aliens and time travel.
However they came about, such unsolved conundrums seem tailor-made to twist mankind's collective melon and force anyone desperate for answers to concoct ever more bizarre theories.
What is the cause of these historical puzzles? Ancient aliens? Psychic powers? Ruptures in the time-space continuum? Magic? Almost certainly not, but when confronted with some of these intractable mysteries, the human mind goes to some pretty weird places.
10. The Tamam Shud Case
In the long, regrettable and storied history of weird deaths, the Tamam Shud case holds a special place as something that seems to have been written for a particularly quirky, blackly humorous murder mystery. Except this one doesn't have an ending, and it's real.
On 1 December 1948, a man's body was found on a beach near Adelaide in Australia. And that's about the only thing that's certain about any of this. He had no ID, or even labels in his clothing.
The only clue was a scrap of paper bearing with words tamam shud, the end line from a 12 century Persian poetry called the Rubaiyat. This rare book was later found in a local taxi cab. It may have had a secret code written in it, but no one has ever translated it.
Tamam shud means 'the end'.
No one ever worked out who the guy was, how he died or what he was doing there. It's possible he was a Cold War spy travelling deliberately incognito, but that just makes things weirder.