The document discusses the origins of Thanksgiving in the United States. It notes that Native American tribes lived in the East Coast areas long before European colonists arrived on the Mayflower in 1621. The following year, the colonists held a harvest feast with the Native Americans that is considered the first Thanksgiving. Today, Americans celebrate Thanksgiving on the fourth Thursday of November, honoring that first feast which included foods like roast turkey, cranberry sauce, potatoes, and pumpkin pie.