The 80th anniversary of the atomic bombing of Hiroshima and Nagasaki is this week. It was the only time nuclear warheads were used during war. Here’s a look at the history and current U.S. stockpile.

The U.S. altered the course of history 80 years ago when it dropped the atomic bomb on Japan. It was an audacious move that ultimately led to the end of World War II. The motivation and secrecy ...