Spanish flu victims at a barracks hospital on the campus of Colorado Agricultural College, Fort Collins, Colorado, in 1918. Even the Spanish flu, which killed an estimated 100 million people, did not cause a prolonged downturn. Photo: Getty Images
Spanish flu victims at a barracks hospital on the campus of Colorado Agricultural College, Fort Collins, Colorado, in 1918. Even the Spanish flu, which killed an estimated 100 million people, did not cause a prolonged downturn. Photo: Getty Images