All great civilizations eventually collapse. It's inevitable. So what are the signs of their demise? On the latest edition of Odd Lots, we speak with Arthur Demarest, a professor at Vanderbilt University who specializes in the end of civilization. Demarest is an anthropologist and archaeologist who's most well known for his work on the Mayans. He tells us about his work, what he's learned -- and what we should be watching out for today.