In early August 1945, warfare changed forever when the United States dropped two atomic bombs on Japan, devastating the cities of Hiroshima and Nagasaki and killing more than 100,000 people. America’s immediate goal was to hasten Japan’s surrender, end World War II and avoid further Allied casualties. But it also wanted to showcase to the world—the Soviet Union in particular—the hugely destructive power of its new technology. The images of Hiroshima and Nagasaki below illustrate that power: what Japan’s Emperor Hirohito called in his statement of surrender “a new and most cruel bomb.”

Hiroshima: Before and After

Aerial view of Hiroshima, Japan

On August 6, 1945, at 8:15 a.m., the crew of the B-29 bomber Enola Gay dropped the first wartime atomic bomb over Hiroshima, Japan, a bustling regional hub that served as an important military communications center, storage depot and troop gathering area. The bomb, code-named "Little Boy," detonated with an estimated 15,000 tons of TNT, destroying five square miles of the city and directly killing some 70,000 people. Final casualty numbers remain unknown; by the end of 1945, injuries and radiation sickness had raised the death toll to more than 100,000. In subsequent years, cancer and other long-term radiation effects steadily drove the number higher.

The National Archives
The downtown Hiroshima shopping district, c. 1945. After the bombing, only rubble and a few utility poles remained.
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A man wheels his bicycle through Hiroshima, days after the city was leveled by the atomic bomb blast<em>.&nbsp;</em>The view here is looking west/northwest, about 550 feet from where the bomb hit.
The National Archives
Looking upriver on the Motoyasu-gawa River, circa 1945.
Rolls Press/Popperfoto/Getty Images
View of the Hiroshima Peace Memorial with the Atomic Bomb Dome (Genbaku Dome), seen from the bank of the Ota River in Hiroshima, Japan in 1965, 20 years after the atomic bomb blast that destroyed the city center.

Nagasaki: Before and After

Aerial view of Nagasaki, Japan

Three days after the destruction of Hiroshima, another American bomber dropped its payload over Nagasaki, some 185 miles southwest of Hiroshima, at 11:02 a.m. Not the original intended blast site, Nagasaki only became the target after the crew found that city, Kokura, obscured by clouds. The Nagasaki explosive, a plutonium bomb code-named “Fat Man,” weighed nearly 10,000 pounds and was built to produce a 22-kiloton blast. Its destructive force wiped out about 30 percent of the city. Some 60,000 to 80,000 people died in Nagasaki, both from direct exposure and long-term side effects of radiation. 

Topical Press Agency/Hulton Archive/Getty Images
The harbor at Nagasaki, Japan, c. 1920. A Christian church can be seen in the foreground.
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Among the&nbsp;<em>few buildings that survived a</em>fter the plutonium bomb decimated Nagasaki was the same Christian church as above.
Keystone-France/Gamma-Rapho/Getty Images
A street in Nagasaki, Japan, c. 1940.
Hulton Archive/Getty Images
The ruins of Nagasaki after the dropping of the atomic bomb, seen from street level.

VIEW MORE: Photos of the Bombing of Hiroshima & Nagasaki

READ MORE about Hiroshima and Nagasaki on HISTORY.com:

Hiroshima, Then Nagasaki: Why the US Deployed the Second A-Bomb

Harry Truman and Hiroshima: Inside His Tense A-Bomb Vigil

The Man Who Survived Two Atomic Bombs

The Hiroshima Bombing Didn't Just End WWII—It Kick-Started the Cold War

‘Father of the Atomic Bomb’ Was Blacklisted for Opposing the H-Bomb