Minnesota is the land of 10,000 lakes. It's also home to some other bodies of water, some of them rather odd. One such odd formation is the Devil's Kettle, which stems off of the Brule River.
About 1.5 miles from the river's mouth, it split into two over a mass of rock. The eastern part flows over a 50 foot waterfall and continues on. The western flow falls 10 feet into a hole and then disappears into the ground. The source of this has yet to be found.
Some believe the water rejoins the river later or has a separate outlet to Lake Superior, but this has not been confirmed. Researchers have tried to locate the outlet by putting colored dyes and ping pong balls into the Devil's Kettle but to no avail. There is even a legend that a car disappeared into the sink hole but this is highly unlikely.