More details about nuclear weapons:

Nuclear weapons use special types of radioactive materials (called fissionable isotopes) to make explosions much larger than anything possible with chemical explosives.

The largest chemical bomb publicly described is the so-called MOAB (“Mother of All Bombs”) fuel-air explosive recently announced by the United States Air Force to have an explosive force equal to 41,000 pounds (just over 20 tons) of TNT.

By comparison, the average nuclear weapon on an intercontinental ballistic missile (ICBM) has an explosive force (or yield) of over 150,000 tons (150 kilotons) of TNT. Nuclear weapons have been made and tested with yields of up to 50 million tons (50 megatons) of TNT.

The smallest nuclear weapons the public knows about have explosive yields of from five hundred tons to five thousand tons of TNT – between 25 and 250 times greater than the MOAB, the biggest chemical bomb we know about.

The Japanese cities Hiroshima and Nagasaki were destroyed by nuclear weapons by the United States, in the hope that the resulting massive destruction would end World War II without an invasion of the Japanese home islands.

World War II did end shortly after the destruction of Nagasaki (the second and last use of nuclear weapons in a war).

Experts estimate that these bombings (which unfortunately killed or maimed hundreds of thousands of people in Hiroshima and Nagasaki) saved a total of from five to ten million lives – the number of Japanese and American troops that might have died had nuclear weapons not ended World War II early.

The deaths of the citizens of Hiroshima and Nagasaki horrified millions of people all over the world, and led to several attempts over the next fifty years to either outlaw nuclear weapons altogether or to restrict the number and size of these weapons – a process called nuclear arms control, nuclear disarmament, or strategic arms limitation.

“Strategic arms” is a euphemism used by government officials mostly for nuclear weapons, although the term has also been applied to biological weapons – specifically, when the Soviet Union filled warheads with anthrax and smallpox to be delivered to American cities by intercontinental ballistic missiles in the mid-to-late 1980s.