March 7, 2014
Scientist say the three-day explosion that began June 6, 1912, spewed ash as high as 100,000 feet above the sparsely populated Katmai region, covering what became known as Alaska's Valley of Ten Thousand Smokes to depths up to 700 feet.
The volcanic cloud spread across the U.S. and traveled as far as Algeria in North Africa.
There were no eruption-related deaths, but forests and untold animals were killed outright. The region's salmon populations was decimated before recover began in the 1920s.