The end of the cold war and ongoing arms-control efforts by the U.S., Russia and other countries have greatly reduced the threat of global nuclear annihilation. But rogue nations and continued tensions make a local exchange of nuclear firepower all too real.
A single detonation can cause horrible death in several ways. The Hiroshima blast—equal to about 15 kilotons of TNT—generated supersonic wind speeds that crushed concrete buildings near ground zero. Heat from the blast scorched to death anyone within one kilometer. People many kilometers away eventually succumbed to radiation poisoning and cancer.