Jim and Marie Bohlen were prominent members of the Canadian Chapter of the Sierra Club, an American ecological organisation. When they thought of the idea to sail a boat to Amchitka, the Sierra Club in America objected, so a splinter group, the "Don't Make a Wave Committee," was formed which later became Greenpeace. There was always concern that US nuclear tests in Amchitka would cause tidal waves and earthquakes in the geologically unstable region of Alaska. In 1969 10,000 people blocked a major US-Canadian border crossing, carrying placards which read: "Don't Make a Wave. It's Your Fault if Our Fault Goes," hence the name.