There is discussion of the history of the holiday thanksgiving and why it’s a day of mourning for Indigenous Americans and of the history of the first Thanksgiving in 1621, with an emphasis on the pre-history:
I have friends who fast and pray all day on Thanksgiving.
Some have worked on various (north and south) reservations in the U.S., worked or are working for people who living on the rez. Some are lifelong students of the teachers who still choose to live in these places.
John Trudell’s 1980 Thanksgiving Day speech: