Most of the trees decorated for Christmas don't naturally grow in a perfect cone shape -- so how do they get that way, and why did we decide on that shape in the first place? Learn about the history of Christmas trees in this episode of BrainStuff.Learn more about advertising on the HowStuffWorks podcasts at www.howstuffworks.com/advertisers.htmAnd to learn about your ad choices when listening to podcasts, visit https://www.howstuffworks.com/privacy.htm#ad-choices
