Elizabeth Fenn, an associate professor of history at the University of Colorado, poses for a photo at Colorado Public Radio on Thursday, April 23, 2015.

(Hart Van Denburg/CPR News)

As CU Boulder professor Elizabeth Fenn worked at her desk this past Monday, she received an obscure email congratulating her on her award. She was confused, until a quick Google search revealed that she was this year's recipient of the Pulitzer Prize in history. She won for her book, "Encounters at the Heart of the World: A History of the Mandan People," and spoke with Ryan Warner about her work, and the Mandans, who lived in present-day North Dakota.