Mysterious disappearing waterfall in Minnesota baffles geologists

There's a mystery in Minnesota that has geologists and nature lovers scratching their heads. Just where is all the water going that plunges from a waterfall and gushes into a large hole underneath? Where does it come out?

It involves a section of the Brule River in a state park in northeastern Minnesota. At that point, the river divides, and one waterfall takes water down the mountain. The other, Western Branch, goes into the hole.

It's called the Devil's Kettle. The hole is too deep and dangerous to explore. Researchers have tried pouring dye, ping pong balls and logs into the hole but they have never been found coming out somewhere else.

So for now, it will have to remain one of nature's mysteries.