7. The Wow signal
In 1977, James Ehman, a volunteer researcher with the Ohio State University’s Big Ear radio observatory (which is now defunct), while examining signals that were received a few days earlier, came across an unfamiliar vertical column with the alphanumeric sequence “6EQUJ5” – something that was so surprising that Ehman circled the sequence, writing “Wow!” alongside it, thus giving the signal its name. What was so wow about this, you ask? Upon tracing the signal – which lasted almost 72 seconds – it was found to have originated from the constellation Sagittarius, and several attempts to receive the signal again were unsuccessful, making the Wow signal perhaps the only extraterrestrial signal to reach Earth.(source)
8. The Dancing Plague of 1518
The phrase “dance till you drop” had very different implications in France back in 1518. One fine day, out of the blue, a lady by the name of Frau Troffea began dancing in the streets of Strasbourg. And that was all she did: she danced, and danced, for days on end. And just as the village elders began whispering about possessions and exorcisms, a neighbour joined in; and then some more. By the time the week came to a close, the dancing had really not: the number of people dancing on the streets had now multiplied to 30. Within a month, 400 people were afflicted by this mysterious dancing epidemic. And by some strange logic, people believed that this epidemic could only be cured by more dancing, and thus encouraged it with much fanfare. Assistance was sought once the dancers began to drop dead from heart attacks, strokes or sheer exhaustion.(source)
The reasons for this remain shrouded in mystery even today.
9. The Taos Hum
Several residents of the scenic city of Taos, located in north-central New Mexico claim to hearing a hum of sorts, the origin of which has not been traced, and has led to speculations spanning from stories of stoned hippies to underground UFO bases. Reported first in the 1990s, the “Taos Hum”, as it has now come to be known, has been heard by more than 2% of the residents. Despite several attempts at unearthing the source of the hum, nothing has turned up.(source)
Apparently, the Moai statues are not the only mystery that the Easter Island houses; in the 19th century, an ancient artifact was unearthed, containing several etchings and symbols which appear to be a form of writing. Christened the Rongorongo tablets, these are believed to contain clues regarding the collapse of the Easter Island civilisation and are believed to have originated sometime around the 13th century.
The language – or, some say, “proto-language” – which the tablets have been written in has proven, thus far, to be indecipherable, posing quite the problem for cryptographers and historians alike.(source)
11. The Tamam Shud case
On December 1, 1948, the body of an unidentified man was found on Somerton Beach in Australia, with the labels torn off his clothes. In the pocket of his trousers was found a tiny scrap of printed paper, which contained the words “Tamam Shud”, the final words in Omar Khayyam’s “Rubaiyat”. The book from which it was apparently torn was discovered a few months after the incident; to complicate matters further, faint writing was discovered on the back of the book, which included a local phone number, along with several lines of cryptic writing, which seemed like a cipher of sorts. A cipher which, by the way, still remains unsolved, much like the murder of the Somerton Man.(source)
12. The Sleeping Sickness of Kazakhstan
First reported in 2013 in Kalachi, a village in the northern part of Kazakhstan, a large number of people – so far, 14% of the population has been affected – seem to be falling asleep for a great length of time, waking only after weeks spent in slumber in a state that doctors describe as comatose. People afflicted by this sickness – causes of which remain unknown – slip into an instantaneous and rather long-lasting deep sleep, waking up feeling confused and dizzy; some also suffered from hallucinations.
Many theories have tried to explain this phenomenon, including an increase in brain fluid, and the effect of a uranium mine in the vicinity from the days of the Soviet Union. However, no answer has been ascertained thus far, making the sleeping sickness a great, unanswered question.(source)