Mount St. Helens National Volcanic Monument

At 8:32 AM on 18 May, 1980, Mount St. Helens violently erupted in what remains to this day the most destructive volcanic eruption in US history. The blast hurled debris at speeds of more than 500 mph (800 km/h), instantly transforming the vibrant forest into a barren wasteland. Ashfall from the eruption was reported as far away as Oklahoma and Ontario (the one in Canada, not the one in California). 42 years later, the present-day landscape remains eerily frozen in time, still resembling a moonscape instead of a forest. It's an ominous reminder of the explosive and violent geologic history that lies largely concealed under such a beautiful state.