1900-1971 Frozen Niagara Falls

Sitting athwart the U.S.-Canada border, Niagara Falls (the collective name for Horseshoe, American and Bridal Veil Falls) dump an average of 4 million cubic feet of water over a 167-foot drop every minute.

Combined, the falls have the highest flow rate of any waterfall worldwide, making them not only spectacular tourist destinations but critical sources of hydroelectric power.

Winters in upstate New York and Ontario can be bitterly cold, and significant portions of the surface of the falls have frozen more than once.

While water still flows beneath the surface, the ice has sometimes been thick and stable enough for brave souls to venture out and walk along the precipice. In 1912, three people were killed when the section of ice they were walking across broke free and plunged over the falls.

The only known time that the falls have frozen virtually solid was in March 1848, when the ice piled up above the lip of the falls slowed its mighty flow to little more than a trickle.