There are pictures of Knights fighting Snails in old Medieval manuscripts - and nobody knows why.
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A waterfall known as The Devil's Kettle empties water into a hole and nobody knows where it ends up!
18
The Platypus used to be considered a myth like Bigfoot and the Yeti.
18
There is a 600 year old 240 paged book called the Voynich Manuscript, that’s written language is still completely unknown today.
15
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.
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