At the turn of the 20th century America was on the move. It was changing from a country of farmers and small towns into a nation of growing urban centers. First railroads, then cars made it possible for people to crisscross the nation. Immigrants poured in from across Europe. Many argue that this transformation turned the country into an industrial powerhouse and later enabled it to become the global leader it is today. But it also created the perfect killing fields for serial murderers. Killing fields because nobody knew who their neighbors were any more. Killing fields because pockets of poverty exploded with people who were lost to mainstream America. And killing fields because serial killers could move from one law enforcement jurisdiction to another and nobody would realize they had a heinous murderer in their midst.