The United States is like a giant jigsaw puzzle, with each state having a uniquely shaped border to fit into its neighboring states. Americans are familiar with each state's shape, but how did those shapes come about? That's what this series, hosted by former ``Daily Show'' correspondent Brian Unger, explains. Unger crisscrosses the country talking to local experts and everyday people in search of the stories behind the boundaries. Religion, transportation and Mother Nature are just a few of the factors that have caused the states' borders to evolve over time, some of which may be continuing to evolve.