In June 1969, the US Army Corps of Engineers did something almost nobody thought possible: they shut off the American side of Niagara Falls. For roughly five months, the thunder of one of the world's most famous waterfalls went silent while engineers walked on the bare riverbed of the Niagara River.

The reason was practical. Decades of erosion had piled up massive talus boulders at the base of the American Falls, and geologists feared the entire cliff face was at risk of collapse. To study it, crews built a temporary cofferdam across the river — a 600-foot earthen barrier that diverted the entire flow over to the Horseshoe Falls on the Canadian side.

The video walks through how the diversion worked, what investigators found on the exposed rock face (including two bodies and millions of coins), and why engineers ultimately decided not to remove the rockfall. It's a great case study in how civil engineers approach a problem most people never even think about: managing the slow geologic decay of a natural landmark.

Caveat: the title leans clickbait and the channel is tiny, but the underlying story is genuinely well-documented history and the engineering details are accurate.