Well for one Aliens, then Nessie (loch-nest monster) and Bigfoot.
There's many more like Mermaids and fairyland but we all know that fairyland is a bit wacko. Hope I helped but as I said there's millions more.
where is death
One of the world's unsolved mysteries is Stonehedge. Another are the face sculptures made of rock on Easter Island. Another are the Seven Wonders of the World.