Built in 1826 by Nathan Cooper, Cooper's Mill is a well-known trail head along the Black River that eventually leads to several waterfalls. However the mill itself is produces a curiosity of its own.
Served by a very leaky sluice which freezes in winter it produces a magnificent ice cave during the cold months. Joel Simpson, an Atlas Obscura reader, was there in December 2010 and captured some of the images displayed above. It's colder there than in the surrounding area, so it freezes sooner and lasts longer.
Be very careful about going inside the ice cave that develops in the winter since it's extremely slippery. If you do go, wear waterproof boots and stay in the flowing water, rather than on the ice, and you'll stay standing. Do as little damage as possible to the ice formations.
Cooper's Mill, though, is an attraction all year long. Known as the site of many state-of-the-art innovations of its time; it always kept current on the latest designs. Many were dreamed up and implemented by inventor Oliver Evans, whose ideas revolutionized the milling process by automating it.
Powered by the natural flow of water, the mill both a huge man-made achievement and environmentally friendly. The 16-foot water wheel at the mill weighs about 13,000 pounds, but it only takes about two cups of water in less than half of the 48 buckets on the wheel to keep it spinning at four RPM. The wheel is most efficient at eight RPM, where it can create up to 45 horsepower.