Lassen Volcanic: America's least visited National Park.

When Mt. Lassen erupted in May 1915 it caught the imagination of the American public. Nearby San Francisco was hosting the Panama Pacific Exhibition to celebrate the 1914 opening of the Panama Canal. It was also a statement to the world that San Francisco had fully recovered from the destructive 1906 earthquake. But the massive volcanic eruption reminded San Franciscans of the unpredictable power of Mother Nature. And in 1916 Lassen Volcanic became a National Park.