Because of the Cold War, various countries entered an unbridled race to develop nuclear weapons. By around 1985, the total destructive power of nuclear weapons accumulated by the five nuclear powers was estimated at 22,000 megatons (22 billion tons; TNT equivalent). This is equal to 1,470,000 bombs of the type dropped on Hiroshima. Based on simple calculations, this volume is enough to kill about 200 billion people, or the present population of the planet more than 35 times over.
Bombs have made great technological strides as well; improved missile guidance technology in particular has raised target accuracy and thus markedly increased the power of nuclear weapons. The Tomahawk Cruise Missile was loaded on nuclear warheads during the Persian War in the Middle East in January to March 1991. With the flight pattern to its target memorized by a computer, it can automatically correct its course during flight and hit its mark with high reliability.
Other methods of transporting nuclear weapons include the stealth bomber, featuring a special surface that prevents detection by enemy radar, and submarines that can secretly launch missiles.
Over the 50 years of the nuclear arms race, nuclear weapons have become smaller, transport distance has lengthened, accuracy has improved, the number of warheads that can be loaded onto a single delivery device has increased, and strategic and tactical nuclear weapons have diversified.