10. Flu pandemic
We might not think of the flu as something that can kill us, but it’s a real possibility. What’s so concerning about the flu is that it’s unpredictable, and the virus that causes it is always adapting and evolving, making it possible that a strain will emerge that is both particularly dangerous and hard to control. The flu pandemic that occurred in 1918 infected an estimated 500 million people worldwide and killed somewhere between 50 and 100 million people. The terrifying reality is that a pandemic like that could happen again someday.