A quote: "Today I found out about the Tunguska Event, which was a 1908 explosion estimated to have been nearly 1000 times more powerful than the atomic bomb dropped on Hiroshima in 1945 and about 1/3 as powerful as the largest ever detonated atomic bomb, the Tsar Bomba."<p>The Tsar Bomba was not an atomic bomb, it was a hydrogen bomb with an fission trigger.<p>A quote: "The U.S. had originally planned a series of much larger nuclear strikes that would happen in quick succession after the Hiroshima and Nagasaki bombs, wiping out most of the major cities in Japan, had the Japanese at that point not agreed to surrender."<p>Yes, except that this ("quick succession") wasn't possible -- after Nagasaki we could assemble just one more bomb:<p>Source: <a href="http://www.warbirdforum.com/third.htm" rel="nofollow">http://www.warbirdforum.com/third.htm</a> : "The Third Bomb"<p>Quote: "Timing was important, Tibbets said: 'It was vital that [the Japanese] believed we had an unlimited supply of atomic bombs and that we would continue to use them. Of course, the truth was that we only had one more bomb on Tinian. Delivery of the third bomb was several weeks away.'"<p>The problem was the plutonium supply -- breeder reactors in Hanford, Washington were being used to generate the plutonium, and they could only produce so much material per month.