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