There is a mysterious and loud radio signal known as 'the space roar' that has yet to be explained.
15
A waterfall known as The Devil's Kettle empties water into a hole and nobody knows where it ends up!
18
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
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
There is a 600 year old 240 paged book called the Voynich Manuscript, that’s written language is still completely unknown today.
15