Seventy-six years ago, in August, 1945, President Harry Truman made one of the most consequential decisions in history. He ordered U.S. warplanes to drop atomic bombs on Hiroshima and, three days later, Nagasaki, instantly incinerating tens of thousands of civilians. The bombings ended the Second World War while ushering in a new age, where human beings harnessed science and technology to create weapons of previously unimaginable power. In this episode, world-renowned war historian Sir Antony Beevor answers one of the most difficult questions to arise in the aftermath of the war: was it necessary to drop the bomb?