President Obama visits Hiroshima's Peace Memorial Park.

On August 6, 1945, the United States dropped the first of two atomic bombs on the small island nation of Japan – the only time a nuclear weapon of mass destruction has been deliberately used to annihilate an entire city. Three days later, on August 9, 1945, the U.S. dropped another atomic bomb on another city in Japan, a mere 261 miles -- less than the distance between Los Angeles and Las Vegas -- from the first.Because of the overwhelming devastation and resulting chaos, the actual mortality of the bombings of Hiroshima and Nagasaki will never be known. However, the latest figures indicate the number killed in Hiroshima is now over 192,000 (either instantly or within the following few months) and over 75,000 in Nagasaki. This is more than six times the number of women, children and men living in Culver City, where I reside. In addition to the deaths, over seven decades later, untold numbers of survivors and their children continue to suffer from radiation and other after effects,This year Barack Obama was the first U.S. president to visit Hiroshima while in office, breaking the silence of nine previous presidents since Truman pressed the buttons. During this interval, many scholars have come to the same conclusion that Gen. Dwight Eisenhower voiced at the time: that Japan was already defeated and the bomb was completely unnecessary. Although Obama did not apologize on behalf of the United States, as some have long wished for, his visit, with all the pomp and ceremony befitting of a state visit -- as well as his personal homage to the victims -- was historic and long overdue.Today we, as Americans, don't take the time or effort to collectively memorialize this atrocity, but there was a time when we did. During the Vietnam War, Asian Americans spoke out at national and international commemorations held regularly in August to remember these tragedies -- in large part to remind the U.S. public that the atomic past was the genocidal present. Here is a look back at a few of these tributes and memorials.Before physicist Michio Kaku became a best-selling author and renowned popularizer of science, in 1973 he was the keynote speaker at a Hiroshima Day Commemoration where he and other scientists took a public oath not to participate in war research. Kaku pointed out that although one atomic bomb was quite enough to devastate the small island nation of Japan, because there were two different bombs -- uranium and plutonium -- the U.S. wanted to test both on live targets. He added that the equivalent of a Hiroshima bomb had been dropped on Vietnam and Cambodia every week for seven years. "The casualties of Hiroshima and Nagasaki number in the hundreds of thousands. The casualties of Vietnam and Cambodia number in the staggering millions."Mike Murase was part of an American delegation to the 17th World Conference Against the A & H Bomb held in Hiroshima, Nagasaki and other cities in Japan and Okinawa in 1971. He addressed audiences of many thousands. "I come to you as a citizen of America. I come to you as a person born in Japan. I come to you as a minority person living in racist America. I come to you as a representative of Asian Americans for Peace." Murase recalled that in Hiroshima, seeing the hands on the clock frozen at 8:15, the dark shadows of human beings seared on concrete posts, and the naked skeleton of the atomic dome were so moving, "they melted away any hard line political edges and made me feel softly spiritual."And at a Hiroshima/Nagasaki Day event in New York in August 1971, a multi-generational group called Asian Americans for Action (known as Triple A) distributed 2,000 cellophane packets of ashes, along with a picture of Cambodian Buddhist priest Ta You, who had died on July 8, 1970 from napalm-related injuries. Designed by artists Arlan Huang, Karl Matsushita, and Jim Tsang, stapled to each packet was a card with the following poem by Vietnamese patriot Ngo Vinh Long:On the other side of the card was printed: "Hiroshima–Nagasaki, August 6, 1945–August 9, 1945. Must it continue?"The atomic bombings of Hiroshima and Nagasaki sparked a world wide anti-nuclear movement that continues to this day. The Comprehensive Nuclear Test Ban Treaty was adopted by the United Nations in 1996 but the US has still not ratified it. If, as David Krieger the president of the international Nuclear Age Peace Foundation, said, "The path to assuring humanity's future runs through Hiroshima and Nagasaki's past," despite the absence of organized commemorations, it would behoove each of us to remember Hiroshima and Nagasaki and work to assure that nothing even remotely similar ever happens again.