In partnership with
Photo Credit: McGhiever, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons
Before You Scroll
At a waterfall in Minnesota, a river splits in two. One half continues downstream, while the other plunges into a dark hole that once appeared to lead nowhere.
The Devil’s Kettle
The Brule River races through Judge C. R. Magney State Park in northeastern Minnesota before reaching a formation known as the Devil’s Kettle. There, a mass of ancient volcanic rock divides the river. The eastern channel tumbles over a conventional waterfall, while the western channel drops into a deep, churning pothole and vanishes from sight.
For generations, visitors wondered where the missing water went. Possibilities included an underground tunnel leading to Lake Superior, a hidden cavern, or a subterranean route crossing beneath the river. People reportedly threw sticks, colored objects, and other items into the kettle, only to watch them disappear.
The geology made the underground-river explanation doubtful. Long caves and drainage passages commonly form in soluble rock such as limestone, but the North Shore is built from hard volcanic formations that do not readily develop those systems. Even so, the absence of an obvious exit kept the mystery alive.
In 2016, hydrologists from the Minnesota Department of Natural Resources measured the river’s flow above and below the falls. They recorded approximately 123 cubic feet per second upstream and 121 cubic feet per second downstream. That difference fell within the normal margin of measurement error.
The water was not leaving the river at all. It was plunging into the kettle, churning violently through the pothole, and rejoining the Brule beneath or immediately downstream of the falls. The supposed missing half was present in the downstream measurement.
The failure of thrown objects to reappear is less mysterious when one considers the force inside the kettle. Powerful recirculating currents can trap, batter, break apart, waterlog, or conceal debris before releasing the remains downstream. A branch entering whole might not return in recognizable condition.
The Devil’s Kettle did not require a secret tunnel to Lake Superior. Its illusion was created by turbulent water, dark rock, an obscured exit, and our understandable suspicion that anything entering a hole called the Devil’s Kettle probably has questionable travel plans.
1,000+ Proven ChatGPT Prompts That Help You Work 10X Faster
ChatGPT is insanely powerful.
But most people waste 90% of its potential by using it like Google.
These 1,000+ proven ChatGPT prompts fix that and help you work 10X faster.
Sign up for Superhuman AI and get:
1,000+ ready-to-use prompts to solve problems in minutes instead of hours—tested & used by 1M+ professionals
Superhuman AI newsletter (3 min daily) so you keep learning new AI tools & tutorials to stay ahead in your career—the prompts are just the beginning
At a Glance
Where is the Devil’s Kettle? On the Brule River in Judge C. R. Magney State Park, Minnesota.
What happens there? The river divides, and one branch plunges into a deep rocky pothole.
Does the water disappear underground? No. Flow measurements show that it rejoins the river at or below the falls.
How was the mystery tested? Hydrologists compared the volume of water upstream and downstream.
What did they find? The upstream and downstream flows were essentially equal within measurement tolerances.
Why did thrown objects disappear? Turbulence may trap, damage, submerge, or disperse them before they emerge.
Could a cave carry the water away? The hard volcanic geology makes a large hidden drainage system unlikely.
Is it still mysterious? Its broad destination is known, although the exact underwater route through the turbulent formation is difficult to observe directly.
Artistic cutaway view conception of how the water may be flowing right back into the river at the base of the falls.
Downstream measurements tell us the water re-enters the river pretty quickly.
Coming Tomorrow: The Plant That Eats Metal — a small shrub capable of packing its leaves with astonishing amounts of nickel.
Editor’s Note: We here at Grapevine publishers read 1440 every day. Highly recommended for unbiased news reporting.
Tired of news that feels like noise?
Every day, 4.5 million readers turn to 1440 for their factual news fix. We sift through 100+ sources to bring you a complete summary of politics, global events, business, and culture — all in a brief 5-minute email. No spin. No slant. Just clarity.