H/T Mental Floss.
It is something that is hard to wrap your mind around Niagara Falls with no water flowing.
What could be more of a spectacle than Niagara Falls, that 11-story cascade of water made up of the Horseshoe (Canadian), American, and Bridal Veil Falls near the United States and Canada border?
Niagara Falls—drained and without the water.
The once-in-a-lifetime event happened on March 28 and March 29, 1848, when ice that had formed over Lake Erie began to break up. Carried by a strong wind across the lake and picked up by the water current, the ice settled in the mouth of the Niagara River. Then it got chilly again, and the fragments turned into a solid dam between Buffalo and Fort Erie. The millions of tons of ice were so strong that it strangled the water flow, effectively turning off the faucet of the Falls and drying up the riverbed from Fort Erie to the crest.
When nearby flour mill workers noticed that their water wheels had stopped working, they headed over and stood, incredulous, at the now-dry riverbed. Muskets and weapons believed to be from the 1814 Battle of Chippawa and discarded in the water were exposed. Some observers retrieved pine timber; others carried torches across, seemingly to honor the moment.
The scene was so dramatic that some believed it was a sign of the end of the world. Churches held special services to pray the water would begin flowing again.
The entire event lasted less than 30 hours. When the wind reversed course, the ice began to break up. It would be over a century before the Falls went dry again. This time, it was on purpose.
From June 25, 1969, to November 25, 1969, the U.S. Army Corps of Engineers built a 600-foot dam across the American Falls so geologists could study the rock formations underneath and try to dislodge boulders that had accumulated at the bottom, cutting off its length. The dam took 27,800 tons of rock and soil to divert the water.
As the geologists worked, a walkway was built to accommodate tourists eager to see the dry landscape. When the geologists finished, the dam was knocked down. It took less than a day for the Falls to do the rest, flowing normally later that night. (Scientists decided to leave those boulders alone, thinking it was better not to mess with nature.)
If you think this was a sight to behold, there’s a good chance it will happen again in our lifetimes. The state of New York intends to dewater the Falls at some point in the coming years to repair two 115-year-old pedestrian bridges that lead to Goat Island. Only the flow of the American Falls will be diverted, which makes up roughly 15 percent of the water. While the remaining flow will be 15 percent stronger, visitors will still see a portion dewatered. New York State just has to get the $26 million in needed funding to make it happen—something nature accomplished for free back in 1848.