top of page

On this day...Aug. 6, 1945: Codename ‘Little Boy’Atomic destruction of Hiroshima sets in motion 75

This map shows a ring of Nike missile bases protecting Pittsburgh from Soviet bombs. Most of the bases were decommissioned by the 1970s.

By Jamie Wiggan


When the 9,000-pound atomic warhead known as “Little Boy” detonated over the Japanese city of Hiroshima Aug. 6, 1945, an estimated 60,000 people lost their lives immediately. In the years following, many thousands more withered and died from radiation exposure.

The immediate effect of Hiroshima — and a second atomic attack on Nagasaki — was to force Japanese surrender and bring an end to World War II. More permanently, the arrival of nuclear weaponry recast the basic currency of military power, setting the tone for the Cold War and present conflicts with Iran and North Korea.

Potsdam Conference

On July 16, 1945, allied leaders Harry Truman, Winston Churchill and Josef Stalin convened in Potsdam, Germany to iron out a strategy for ending the war and rebuilding a shattered Europe. Germany had surrendered two months previously, but Japan still hung on.

Desperate for an end after six years of warring, the allies concluded their 13-point Potsdam declaration with a stark warning:

“We call upon the government of Japan to proclaim now the unconditional surrender of all Japanese armed forces…The alternative for Japan is prompt and utter destruction.”

Unaware of the newly developed atomic bomb, which could substantiate the allies’ threats, Japanese officials skeptically debated the surrender request at the time “Little Boy” scorched Hiroshima.

Three days later, a second, larger bomb known as “Fat Man” obliterated the Japanese harbor town of Nagasaki, claiming 40,000 lives within minutes. Although the bomb was more powerful, the hilly contours of the harbor town limited the bomb’s destruction.

Japanese leaders saw their position was hopeless and conceded defeat. In announcing the surrender to his people, Emperor Hirohito made his first ever public radio broadcast.

“The enemy has begun to employ a new and most cruel bomb, the power of which to do damage is, indeed, incalculable, taking the toll of many innocent lives,” he said. “Should we continue to fight… it would lead to the total extinction of human civilization.”

Cold War

Hirohito’s words came to define the feeling of ordinary citizens around the world who lived through a constant backdrop of nuclear fear during the height of the Cold War.

Soon after emerging from World War II as victorious allies, ruptures began to show between the Marxist Soviet Union and the capitalist Western Bloc.

The two powers scrambled for dominance over unaligned states. The Soviet empire expanded westward, swallowing up much of eastern and central Europe. Defeated Germany was carved up, with the Soviets occupying the East, and Britain and America overseeing the West.

“An iron curtain has descended across the continent,” former British Prime Minister Winston Churchill told an American college audience in 1946, defining the onset of the Cold War.

The United States responded to the perceived Soviet threat by installing anti-aircraft bases around major cities, including Pittsburgh. Initially, these bases housed regular rockets designed to pull down Russian bombers; however, by 1958 these rockets contained small nuclear warheads, each capable of eliminating an entire squadron.

School students prepared for the ever-present threat through repeated “duck-and-cover” drills. In a government-led effort to safeguard the general public, the U.S. Army Corps of Engineers surveyed buildings across the country, marking appropriately shielded structures with yellow and black fallout shelter signs.

After peaking in the 1960s, the nuclear arms race began to taper off in 1972, when President Richard Nixon brokered an agreement with Soviet General Secretary Leonid Brezhnev limiting future arms production.

Nuclear fears continue

Even after the toppling of the Berlin Wall in 1989 closed out the Cold War chapter, the threat of nuclear war has continued to steer foreign policy and negotiations over the balance of world power.

In the wake of 9/11, fear Saddam Hussein’s regime might possess nuclear weapons led to the deployment of more than 160,000 American and allied troops to Iraq in 2003.

Stretching out across eight years, the warring claimed more than 4,000 American lives and inflicted nearly 32,000 casualties.

After the final withdrawal of U.S. troops from Iraq in 2011, world leaders turned their attention to Iran, which, under the leadership of Ayatollah Ali Khamenei, had begun stockpiling reserves of enriched uranium in sufficient quantities for developing nuclear weapons.

Iran agreed to limit uranium production in a 2016 agreement granting oversight to several world powers in exchange for lifted economic sanctions. Two years later, President Donald Trump withdrew the U.S. from the agreement and resumed the sanctions.

In retaliation, Khamenei vowed to quadruple uranium production.

In recent years, North Korea has made strides with its nuclear program, as demonstrated by a series of well-publicized testing.