When we look at the United States, the borders often seem arbitrary, with parts of one state looking as if they belong to another.
Those who love maps and history ponder why. Enough people care that when History ran a special called "How the States Got Their Shapes," it did so well that it spawned a 10-part series, which launches Tuesday, May 3.
Brian Unger, a journalist and former correspondent for "The Daily Show," hosts. Unger logged more than 36,000 road miles and 150,000 air miles making this show.
Each episode is grouped around a theme. In the series premiere, that theme is water. Not surprisingly, states are often defined by access to water.
The episode details an ongoing clash between Tennessee and Georgia. When state boundaries were established, Tennessee received an extra 51 square miles, likely a result of inaccurate surveying equipment.
This becomes important because Georgia, particularly Atlanta, needs water. Unger visits a bar in which the state line runs down the middle.
Water is such a precious resource that some folks say we should forget worrying about oil and concentrate on water. California and Nevada are draining the West's resources. Meanwhile, Maine is flush with water, a result of the glaciers that formed it and pool in the hundreds of lakes dotting the craggy state.
A future episode examines how religion helped establish borders, focusing on "William Penn's dream and the trajectory of the Amish and how it shaped the borders of Pennsylvania," Unger says.
That episode also looks at the Bible Belt. "Why does it run through the South the way it does?" he asks. "What does it mean geographically?"
Another episode focuses on rebels and outliers, who "formed the westward states to escape the East because of fleeing from the law," Unger says.
"I come away from this series and all the miles we covered thinking it is a miracle that we are united, that we are a union," he says.