The Platypus used to be considered a myth like Bigfoot and the Yeti.
18
A waterfall known as The Devil's Kettle empties water into a hole and nobody knows where it ends up!
18
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
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