William Harvey was a scientific pioneer. The 17th-century English physician worked to debunk the claims that phlegm and bile were the cause of all health problems.
Harvey was "fighting against 1,500 years of established scientific dogma," World Science Festival reports. His work heavily influenced modern medicine, so World Science Festival is celebrating him as a "misunderstood genius." Learn more about Harvey's work in the video below. --Meghan DeMaria