Rock Lake, at some 1,300 acres in western Jefferson County, is only about half the size of Pewaukee Lake. Its water is murky, a screen of silt and algae stirred up by the weather. Lake Mills, the town on its eastern shore, has had several businesses with the word “pyramid” in their names: Pyramid City Driving School, Pyramid Silo Services and the Pyramid Motel.
But you won’t see any pyramids above ground. You have to look under the water.
The Lake Mills Chamber of Commerce has promoted a legend that large stone structures lie beneath Rock Lake, dating back hundreds of years. The chamber claims Native Americans built pyramids in a valley, hoping to end a drought, and the gods responded by filling the valley with water.
The modern history of that legend began in the early 20th century, when a variety of divers and local fishermen reported seeing structures in the lake that looked man-made. Most famously, Wisconsin diving pioneer Max Nohl dived into the lake in 1937 and came across a stone structure that “looked like an upside down ice cream cone.”
That’s according to the Rock Lake Research Society, a group of divers, pilots and scientists that launched several expeditions between the late 1990s and early 2000s, resulting in a series of tantalizing photos but no conclusive evidence.
The society and other investigators have enjoyed little to no support from mainstream scientists. Former state archaeologist Bob Birmingham told the Wisconsin State Journal in 2015 that the tales were “a bunch of baloney.” The structures are just rock piles left by glaciers, Birmingham and others say.
In recent years, believers have used sophisticated sonar systems to produce maps of such large shapes as an 18-foot tall, tent-shaped stone pyramid with a 60-foot by 100-foot base. Whether any of the objects are man-made, they still don’t know.