On Thanksgiving Day 1970, Means and other AIM activists staged their first protest in Boston: they seized the Mayflower II, a replica ship of the Mayflower, to protest the Puritans' and United States' mistreatment of Native Americans. In 1971 Means was one of the leaders of AIM's takeover of Mount Rushmore, a federal monument. Rushmore is within the Black Hills, an area sacred to the Lakota tribe.