The exact cause of death and burial site of Genghis Khan is unknown, because all of the 2000 funeral guests and 800 soldiers were killed in order to preserve the secret.
16
There are pictures of Knights fighting Snails in old Medieval manuscripts - and nobody knows why.
23
Since 1982, a radio frequency emanating from Russia has been broadcasting a buzzer-like sound and, periodically, an unknown voice reads orders, names, and numbers. No one knows where exactly it is coming from or what it means.
13
In 1987, a Chicago TV station had its broadcast interrupted by a pirate signal that shows a man in a Max Headroom mask mumbling and being spanked with a fly swatter. Despite investigations by the FCC and FBI, this became the only known incident in which a hacker interrupted a major TV broadcast without getting caught.
19
In 1968, a car driven by bank employees was pulled over by a motorcycle cop claiming the car had been rigged with a bomb. The cop got under the car to “defuse” the device. When the car started to smoke, everybody ran. Then the “cop” just drove the car away. The 300,000,000 Yen robbery remains unsolved to this day.
20
The Platypus used to be considered a myth like Bigfoot and the Yeti.
18
In 1518, a "dancing plague" struck Strasbourg, Alsace, whereby hundreds of people danced fervently in the streets over the period of a month. Some suffered heart attacks or strokes, and many others died from sheer exhaustion. It remains unexplained.
19
There is a mysterious and loud radio signal known as 'the space roar' that has yet to be explained.
15