Indeginous people and supporters occupied the island off the coast of San Francisco between 1969 and 1971. Since then, there has been an annual sunrise gathering to highlight the deadly, destructive impact on indigenous people of the arrival in America of European colonizers more than 400 years ago.
https://www.independent.co.uk/news/world/americas/us-politics/kaepernick-unthanksgiving-day-alcatraz-native-american-celebrations-kneeling-nfl-player-a8074596.html?fbclid=IwAR0fBOfZYHxNtEBiJtr3xrzxkcn-0JjVd3Qn_HblfKX31sljrpdvqlkGpKE