Nuclear weapons are the most dangerous weapons on earth. One can destroy a whole city, potentially killing millions, and jeopardizing the natural environment and lives of future generations through its long-term catastrophic effects. The dangers from such weapons arise from their very existence. Although nuclear weapons have only been used twice in warfare—in the bombings of Hiroshima and Nagasaki in 1945—about 22,000 reportedly remain in our world today and there have been over 2,000 nuclear tests conducted to date. Disarmament is the best protection against such dangers, but achieving this goal has been a tremendously difficult challenge.