Nuclear war
Since the end of Communist rule in Russia and Eastern Europe, tensions between America and Russia have eased and war has become less likely. However, today there is more worry about nuclear proliferation. Countries around the world who already have their own bombs include Britain, France, China, Israel, India, Pakistan and North Korea; as all kinds of technology tend to become cheaper and easier to get and use, there is a fear that nuclear weapons could become available to countries with unstable governments. There is also the possibility that terrorists might be able to capture or build nuclear weapons and use them.