As much of the United States prepares to mark Thanksgiving this weekend, many Native Americans will gather in Plymouth to commemorate the 47th National Day of Mourning. This year is dedicated to water protectors at Standing Rock and to the struggle for recognition of Indigenous Peoples’ Day. To discuss this and more, we speak with indigenous historian and activist Roxanne Dunbar-Ortiz. She is the author of “An Indigenous Peoples’ History of the United States” and co-author of “All the Real Indians Died Off: And 20 Other Myths About Native Americans.”