A: The main cause of rapid population growth is when there are more births than there are deaths, which is referred to as a natural increase. Other causes of ... Full Answer >
Spanish flu (1918-1919). The influenza pandemic of 1918-1919 killed more people than the World War I, at somewhere between 20 and 40 million people. It has been cited as the most devastating epidemic in recorded world history. Known as Spanish Flu or La Grippe the influenza of 1918-1920 was a global disaster.
John Barry, author, The Great Influenza: The Story of the Deadliest Pandemic in History. The year 1918 saw not only the butchery of World War I but a worldwide influenza pandemic. Credible estimates of the death toll range from nearly 2 percent to well over 5 percent of the entire world population.