If a medium-sized nuclear weapon were detonated over a city, everything within a fifty-mile radius of the explosion would be leveled. That said, there are approximately 13,890 nuclear warheads in the world. Russia has about 6,500 and the United States has about 6,185. The first successful nuclear weapons test took place in July 1945. The test was conducted by the United States in New Mexico. Less than a month later, the United States dropped two nuclear weapons on Japan, making it the first country to use nuclear weapons in war. The outbreak of a global nuclear war is the greatest global catastrophic threat facing humanity. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay The development of a nuclear weapon first began with the discovery of nuclear fission, learning how to produce a controlled reaction, and finding a way to use the weapon. German scientists Otto Hahn and Fritz Strassman were the first to discover nuclear fission (Cochran and Norris). They discovered that bombarding uranium atoms with neutrons created a radioactive barium isotope. The neutrons caused the uranium nucleus to break or fission into two pieces. This information was brought to the United States by Neils Bohr. Bohr later learned that each fission process releases on average about two neutrons. If many fission processes were placed close to each other, they would cause a chain reaction that would release a very large amount of energy. After discovering how to produce a controlled chain reaction, the next step was to assemble a weapon in which the fission process could be used. Initially, the weapon was supposed to be a firearm. A piece of uranium-235, also known as plutonium-239, would be inserted into the barrel of a gun and then fired at the target. This idea failed due to the fact that, during the production of plutonium-239, it sometimes absorbed an extra electron which caused it to spontaneously fission and explode prematurely, which is highly dangerous to be nearby. The final decision was to implode the plutonium rather than explode. To do this, there must be a compressed sphere of plutonium surrounded by other explosives. The plutonium was compressed to conserve the amount used so it could be used for more bombs. The final design resulted in a thirteen-pound sphere of plutonium with a small hole drilled in it through which the neutron reactor could pass. Using the process of fission and its fusion counterpart, the world has been able to create approximately 14,000 nuclear weapons. Although the world has a huge arsenal of nuclear weapons, only two nuclear bombs have ever been used. The first nuclear weapon to be used was dropped on the Japanese city of Hiroshima by the United States of America (“History of the Atomic Bomb”). The United States needed a way to convince Japan to surrender. The economic blockade and conventional bombing were not convincing enough to force Japan to step down. On August 6, 1945, the United States dropped the first nuclear bomb, nicknamed "Little Boy", on the city of Hiroshima. “Little Boy” swept away almost everything except concrete buildings. Killed approximately 69,000 civilians and injured approximately 64,000 in Hiroshima (United States, Army, Corps of Engineers, Manhattan Borough). The bombing of Hiroshima did not cause the surrender of Japanese Emperor Hirohito. As a result, the United States decided to launch another nuclear weapon on Japan. The second and last nuclear weapon used was dropped on the Japanese city of Nagasaki. The second.