There are pictures of Knights fighting Snails in old Medieval manuscripts - and nobody knows why.
23
There is a mysterious and loud radio signal known as 'the space roar' that has yet to be explained.
15
In 1958, a nuclear bomb was lost somewhere along the swampy coast of Georgia. Its whereabouts remain a mystery to this day.
29
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
There is an island near Italy that was the site of wars, a dumping ground for plague victims, and an insane asylum. It's considered so dangerously haunted that the Italian government does not allow public access.
78
A waterfall known as The Devil's Kettle empties water into a hole and nobody knows where it ends up!
18