The peaceful beauty of a winter sunset at Crater Lake National Park in Oregon gives few hints of the landscape’s violent past. For approximately 400,000 years, volcanic eruptions built up a 12,000 foot mountain now called Mt. Mazama. 7,700 years ago, the volcano erupted in a cataclysmic explosion. Fatally weakened, the top of the mountain collapsed and created the hole – the caldera – that we now see today filled with pristine blue water. Photo courtesy of Albert Yang.