Every day, a large amount of water from the Brule River flows into this small hole and disappears.
To discover the mystery of Devil's Kettle, scientists have tried to color the river water, release small logs as well as many table tennis balls from upstream to see where the water will flow.
But regardless of the color of the dye, the log, or anything, the water flowing down the Devil's Kettle had vanished without leaving any trace.
Calvin Alexander, a professor at the University of Minnesota, thinks it's possible that Devil's Kettle acts as a giant blender, crushing all the things that flow down with the water, leaving no trace.
But the question " Where is the water after being" crushed "or is it under the" warm "bottomless cave? " There is no answer yet.
In early 2017, Jeff Green, a hydrologist from the Minnesota State Department of Natural Resources (DNR) and professor Calvin Alexander successfully deciphered the 60-year mystery at Devil's Kettle.
Water volume Devil's Kettle waterfall before falling and water at the foot of the waterfall next to almost identical.(Photo: Smithsonian Magazine.)
Two experts carried out specialized experiments, measuring the water volume of the river before flowing to the Devil's Kettle waterfall and comparing it to the amount of water at the edge of the waterfall (this water flows to Lake Superior). The results showed that the two volumes of water were nearly equal.
This means that the Devil's Kettle spill does not mysteriously disappear but seeps back up to the waterfall's side leg. Finally, after many years of mystery about "Devil's Kettle", scientists have clarified it after six decades.