Growing up in Mankato, Minnesota, John Biewen says, nobody ever talked about the most important historical event ever to happen there: in 1862, it was the site of the largest mass execution in U.S. history. Thirty-eight Dakota Indians were hanged after a war with white settlers. John went back to Minnesota to figure out what really happened 150 years ago, and why Minnesotans didn’t talk about it much after.

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