There are some pretty terrifying diseases out there, but many people don't realise that the most deadly isn't Ebola or a viral flu strain - it's malaria.
As the Business Insider video above explains, for around 20 million years, the parasite that causes malaria has been plaguing humans and our ancestors.
The mosquito-borne disease halted the armies of Genghis Khan and Attila the Hun in their tracks, and infected George Washington, Theodore Roosevelt, Abraham Lincoln, and John F Kennedy.
It killed Alexander the Great, King Tut, and at least six popes. And according to some researchers, almost half of all humans who ever lived died from malaria.
Between 1900 and 1950 alone, the disease is estimated to have killed 100 million people, and many people don't realise that the Centres for Disease Control (CDC) was founded in 1946 primarily to fight malaria in the US.
Since then, the disease has been eradicated from much of the world thanks to insecticide use, but it still kills more than half a million people every year.
Watch the video above to have your perspective on the disease altered forever.