From the Video Description: "In 1918-1919, the worst flu in recorded history killed an estimated 50 million people worldwide. The U.S. death toll was 675,000 - five times the number of U.S. soldiers killed in World War I. Where did the 1918 flu come from? Why was it so lethal? What did we learn?" The duration of this video is 56 minutes and 49 seconds.