The use of general anesthesia is less than 200 years old. Before doctors were able to cause unconsciousness in patients, surgery was brutal for all involved. But despite this advancement in medicine, science still has no idea how it works.
Redheads are supposedly fiery, passionate people, but is there any truth to these stereotypes? Find out what studies have to say about redheads -- and if they'll really go extinct soon -- in this HowStuffWorks podcast.