On Monday, August 6, 1945, a mushroom cloud billows into the sky about one hour after an atomic bomb was dropped by American B-29 bomber, the Enola Gay, detonating above Hiroshima, Japan. Nearly 80,000 people are believed to have been killed immediately, with possibly another 60,000 survivors dying of injuries and radiation exposure by 1950.

On Monday, August 6, 1945, a mushroom cloud billows into the sky about one hour after an atomic bomb was dropped by American B-29 bomber, the Enola Gay, detonating above Hiroshima, Japan. Nearly 80,000 people are believed to have been killed immediately, with possibly another 60,000 survivors dying of injuries and radiation exposure by 1950.

By 1945, the Japanese had suffered an unbroken string of defeats for nearly two years in the South West Pacific, the Marianas campaign, and the Philippines campaign. In June, after more than 80 days of fighting, Allied forces captured the Japanese island of Okinawa, but at a horrible cost, with more than 150,000 casualties on both sides, and tens of thousands of civilians dead (many by their own hand). Okinawa was seen as a painful preview of a planned full invasion of Japan, and Allied generals predicted massive casualties if it took place.

Following Germany’s defeat, the Soviet Union quietly began redeploying its battle-hardened European forces to the Far East, in addition to about forty divisions that had been stationed there since 1941, as a counterbalance to the million-strong Kwantung Army.

The island-hopping strategy adopted by the U.S. Navy successfully brought B-29 bombers within range of Japan’s Home Islands, and they carried out massive attacks involving high explosives, incendiary bombs, and finally the two most powerful weapons ever used in war: the newly-invented atomic bombs dropped on Hiroshima and Nagasaki.

A North American B-25 makes a bomb run on a Japanese destroyer escort off Formosa in April of 1945.

A North American B-25 makes a bomb run on a Japanese destroyer escort off Formosa in April of 1945.

Six days after the bombing of Nagasaki, and after much internal struggle, Japan surrendered on August 15, 1945. World War II was over. On August 28, the occupation of Japan by the Supreme Commander for the Allied Powers began. The surrender ceremony was held on September 2, aboard the United States Navy battleship USS Missouri, at which officials from the Japanese government signed the Japanese Instrument of Surrender, thereby ending the hostilities. Allied civilians and military personnel alike celebrated V-J Day, the end of the war; however, some isolated soldiers and personnel from Imperial Japan’s far-flung forces throughout Asia and the Pacific islands refused to surrender for months and years afterwards, some even refusing into the 1970s.

The role of the atomic bombings in Japan’s unconditional surrender, and the ethics of the two attacks, is still debated. The state of war formally ended when the Treaty of San Francisco came into force on April 28, 1952. Four more years passed before Japan and the Soviet Union signed the Soviet–Japanese Joint Declaration of 1956, which formally brought an end to their state of war.

This aerial photograph made on day five of the invasion shows the immense power needed to break the back of Japanese Resistance on Iwo Jima, on March 17, 1945. Just off the beach, landing craft await their chance at the unloading area while small boats from the transports ply back and forth bring assault troops and returning wounded for treatment. Further out, the transports themselves faintly along the horizon, the protective screen of destroyers, destroyer escorts and cruisers can be seen. On the island, Marine tanks can be spotted moving through the rough terrain toward the first airfield at left.

This aerial photograph made on day five of the invasion shows the immense power needed to break the back of Japanese Resistance on Iwo Jima, on March 17, 1945. Just off the beach, landing craft await their chance at the unloading area while small boats from the transports ply back and forth bring assault troops and returning wounded for treatment. Further out, the transports themselves faintly along the horizon, the protective screen of destroyers, destroyer escorts and cruisers can be seen. On the island, Marine tanks can be spotted moving through the rough terrain toward the first airfield at left.

With his hands in the air, the first of 20 Japanese emerges from a cave on Iwo Jima, on April 5, 1945. The group had been hiding for several days.

With his hands in the air, the first of 20 Japanese emerges from a cave on Iwo Jima, on April 5, 1945. The group had been hiding for several days.

Anti-aircraft gunners, center foreground, pour a deadly stream of fire into an already-burning Japanese Kamikaze plane plummeting toward the flight deck of the USS Sangamon, a Navy escort carrier, during action in the Ryukyu Islands near Japan, on May 4, 1945. This suicide plane landed in the sea close to the carrier. Another Japanese aircraft later succeeded in hitting the ship deck, inflicting heavy damage.

Anti-aircraft gunners, center foreground, pour a deadly stream of fire into an already-burning Japanese Kamikaze plane plummeting toward the flight deck of the USS Sangamon, a Navy escort carrier, during action in the Ryukyu Islands near Japan, on May 4, 1945. This suicide plane landed in the sea close to the carrier. Another Japanese aircraft later succeeded in hitting the ship deck, inflicting heavy damage.

Flames leap from the deck of the USS Bunker Hill, after it was hit by two Kamikazes in 30 seconds on May 11, 1945 off Kyushu. 346 aboard were killed, another 264 wounded.

Flames leap from the deck of the USS Bunker Hill, after it was hit by two Kamikazes in 30 seconds on May 11, 1945 off Kyushu. 346 aboard were killed, another 264 wounded.

Tanks of the Sixth Marine Division probe the outskirts of Naha, capital city of Okinawa, Japan, on May 27, 1945.

Tanks of the Sixth Marine Division probe the outskirts of Naha, capital city of Okinawa, Japan, on May 27, 1945.

Perched on the rim of a gaping hole in the wall of a theater in the Ryukyu capital, a Marine rifleman views the result of the American bombardment of Naha, Okinawa, Japan, on June 13, 1945. Structure skeletons are all that remain of the city with a pre-invasion population of 443,000 people.

Perched on the rim of a gaping hole in the wall of a theater in the Ryukyu capital, a Marine rifleman views the result of the American bombardment of Naha, Okinawa, Japan, on June 13, 1945. Structure skeletons are all that remain of the city with a pre-invasion population of 443,000 people.

A formation of Boeing B-29 Superfortresses of the 73rd Bomb Wing fly over Mt. Fuji, Japan in 1945.

A formation of Boeing B-29 Superfortresses of the 73rd Bomb Wing fly over Mt. Fuji, Japan in 1945.

Flames spread through the city of Tarumiza, Kyushu, Japan, after incendiary bombing by the 499th Bomb Squadron, 345th Bomb Group.

Flames spread through the city of Tarumiza, Kyushu, Japan, after incendiary bombing by the 499th Bomb Squadron, 345th Bomb Group.

A night view of burning Toyama, Japan on August 1, 1945, after 173 American B-29 bombers dropped incendiary bombs on the city. Formerly a big producer of aluminum, the city was 95.6% demolished.

A night view of burning Toyama, Japan on August 1, 1945, after 173 American B-29 bombers dropped incendiary bombs on the city. Formerly a big producer of aluminum, the city was 95.6% demolished.

After an incendiary bombing, a view of some of the damage in Tokyo, Japan in 1945. A strip of residential buildings remains undamaged, surrounded by ashes and rubble of neighboring structures burned or blasted to the ground.

After an incendiary bombing, a view of some of the damage in Tokyo, Japan in 1945. A strip of residential buildings remains undamaged, surrounded by ashes and rubble of neighboring structures burned or blasted to the ground.

The expanding fireball and shockwave of the Trinity test explosion, seen .025 seconds after detonation in the New Mexico desert on July 16, 1945.

The expanding fireball and shockwave of the Trinity test explosion, seen .025 seconds after detonation in the New Mexico desert on July 16, 1945.

Incendiary bombs are dropped from B-29 Superfortresses of the U.S. Army Air Forces on already-burning landing piers and surrounding buildings in Kobe, Japan, on June 4, 1945.

Incendiary bombs are dropped from B-29 Superfortresses of the U.S. Army Air Forces on already-burning landing piers and surrounding buildings in Kobe, Japan, on June 4, 1945.

The terrible damage done to Tokyo by American bombers can be seen in what was once a residential district in the Japanese capital, viewed months later, on September 10, 1945. Only large well constructed buildings remain intact

The terrible damage done to Tokyo by American bombers can be seen in what was once a residential district in the Japanese capital, viewed months later, on September 10, 1945. Only large well constructed buildings remain intact

In flight over the Japanese city of Kobe, a U.S. Army Air Forces B-29 Superfortress trails smoke and fire, on July 17, 1945.

In flight over the Japanese city of Kobe, a U.S. Army Air Forces B-29 Superfortress trails smoke and fire, on July 17, 1945.

Following the July 26 Potsdam Declaration, where Allies outlined the terms of surrender for Japan and promised

Following the July 26 Potsdam Declaration, where Allies outlined the terms of surrender for Japan and promised “inevitable and complete destruction” of Japan if they failed to comply, preparations were secretly under way to make use of the newly-tested Atomic Bomb. Here, the first nuclear device to be used as a weapon, codenamed “Little Boy”, rests on trailer cradle in a pit, ready for loading into the bomb bay of the “Enola Gay” in August of 1945.

The U.S. B-29 Superfortress bomber

The U.S. B-29 Superfortress bomber “Enola Gay” took off from Tinian Island very early on the morning of August 6th, carrying “Little Boy”, a 4,000 kg (8,900 lb) uranium bomb. At 8:15 am, Little Boy was dropped from 9,400 m (31,000 ft) above the city, freefalling for 57 seconds while a complicated series of fuse triggers looked for a target height of 600 m (2,000 ft) above the ground. At the moment of detonation, a small explosive initiated a super-critical mass in 64 kg (141 lbs) of uranium. Of that 64 kg, only .7 kg (1.5 lbs) underwent fission, and of that mass, only 600 milligrams was converted into energy – an explosive energy that seared everything within a few miles, flattened the city below with a massive shockwave, set off a raging firestorm and bathed every living thing in deadly radiation. At the time this photo was made, smoke billowed in a column 20,000 feet above Hiroshima while smoke from the burst had spread over 10,000 feet at the base of the rising column.

A pall of smoke lingers over this scene of destruction in Hiroshima, Japan, on August 7, 1945, a day after the explosion of the atomic bomb. Nearly 80,000 people are believed to have been killed immediately, with possibly another 60,000 survivors dying of injuries and radiation exposure by 1950.

A pall of smoke lingers over this scene of destruction in Hiroshima, Japan, on August 7, 1945, a day after the explosion of the atomic bomb. Nearly 80,000 people are believed to have been killed immediately, with possibly another 60,000 survivors dying of injuries and radiation exposure by 1950.

The searing heat from the nuclear explosion above Hiroshima scorched the roadway of this bridge across the Ota River, about a half a mile from the focal point of the bomb burst. The areas shielded by the concrete pillars and railings were left undamaged, creating permanent

The searing heat from the nuclear explosion above Hiroshima scorched the roadway of this bridge across the Ota River, about a half a mile from the focal point of the bomb burst. The areas shielded by the concrete pillars and railings were left undamaged, creating permanent “shadows” on the bridge deck.

Hiroshima atomic bombing survivors receive emergency treatment by military medics, on August 6, 1945.

Hiroshima atomic bombing survivors receive emergency treatment by military medics, on August 6, 1945.

The shadow of a handle on a gasometer left an imprint after the August 6, 1945 atomic bomb explosion, two kilometers away from the hypocenter in Hiroshima.

The shadow of a handle on a gasometer left an imprint after the August 6, 1945 atomic bomb explosion, two kilometers away from the hypocenter in Hiroshima.

A Japanese soldier walks through a completely leveled area of Hiroshima in September of 1945.

A Japanese soldier walks through a completely leveled area of Hiroshima in September of 1945.

Only days after the bombing of Hiroshima, the second operational nuclear weapon was readied by the U.S. Called

Only days after the bombing of Hiroshima, the second operational nuclear weapon was readied by the U.S. Called “Fat Man”, the unit is seen being placed on a trailer cradle in August of 1945. When the Japanese still refused to surrender after Hiroshima, U.S. President Truman issued a statement saying in part “If they do not now accept our terms, they may expect a rain of ruin from the air, the like of which has never been seen on this earth.”

“Fat Man” was dropped from the B-29 bomber Bockscar, detonating at 11:02 AM, at an altitude of about 1,650 feet (500 m) above Nagasaki. An estimated 39,000 people were killed outright by the bombing a further 25,000 were injured.

This picture made shortly after the August 9, 1945 atomic bombing, shows workers carrying away debris in a devastated area of Nagasaki, Japan. This picture obtained by the U.S. Army from files of Domei, the official Japanese news agency, was the first ground view of the nuclear destruction in Nagasaki.

This picture made shortly after the August 9, 1945 atomic bombing, shows workers carrying away debris in a devastated area of Nagasaki, Japan. This picture obtained by the U.S. Army from files of Domei, the official Japanese news agency, was the first ground view of the nuclear destruction in Nagasaki.

The only recognizable structure remaining is a ruined Roman Catholic Cathedral in background on a destroyed hill, in Nagasaki, Japan in 1945.

The only recognizable structure remaining is a ruined Roman Catholic Cathedral in background on a destroyed hill, in Nagasaki, Japan in 1945.

Dr. Nagai, medical instructor and x-ray specialist at Nagasaki Hospital, a victim of atomic radiation caused by the nuclear bombing. A few days after this photo was made, Dr. Nagai passed away.

Dr. Nagai, medical instructor and x-ray specialist at Nagasaki Hospital, a victim of atomic radiation caused by the nuclear bombing. A few days after this photo was made, Dr. Nagai passed away.

People walk through the charred ruins of Nagasaki, shortly after an atomic bomb destroyed much of the city. The explosion generated heat estimated at 3,900 degrees Celsius (4,200 K, 7,000 °F).

People walk through the charred ruins of Nagasaki, shortly after an atomic bomb destroyed much of the city. The explosion generated heat estimated at 3,900 degrees Celsius (4,200 K, 7,000 °F).

On August 9, 1945, the Soviet Union invaded Manchuria, sending more than a million soldiers to attack Japan's Kwantung Army. The Soviets quickly defeated the poorly-prepared Japanese, putting further pressure on them to surrender to the Allies. Here, a column of tanks appears on the streets of the Chinese city of Dalian.

On August 9, 1945, the Soviet Union invaded Manchuria, sending more than a million soldiers to attack Japan’s Kwantung Army. The Soviets quickly defeated the poorly-prepared Japanese, putting further pressure on them to surrender to the Allies. Here, a column of tanks appears on the streets of the Chinese city of Dalian.

Soviet soldiers on the bank of the Songhua River in Harbin. The Japanese-occupied city was liberated by Soviet troops on August 20, 1945. Some 700,000 Soviet troops occupied Manchuria by the time Japan surrendered.

Soviet soldiers on the bank of the Songhua River in Harbin. The Japanese-occupied city was liberated by Soviet troops on August 20, 1945. Some 700,000 Soviet troops occupied Manchuria by the time Japan surrendered.

Japanese soldiers surrendering their rifles as a Soviet soldier records information in a book in 1945.

Japanese soldiers surrendering their rifles as a Soviet soldier records information in a book in 1945.

A Japanese prisoner of war at Guam, Mariana Islands, covers his face as he hears Japanese Emperor Hirohito making the announcement of Japan's unconditional surrender on August 15, 1945. World War II had come to an end.

A Japanese prisoner of war at Guam, Mariana Islands, covers his face as he hears Japanese Emperor Hirohito making the announcement of Japan’s unconditional surrender on August 15, 1945. World War II had come to an end.

Sailors in Pearl Harbor, Hawaii listen to radio and cheer as Tokyo radio states Japan has accepted the Potsdam surrender terms on August 15, 1945.

Sailors in Pearl Harbor, Hawaii listen to radio and cheer as Tokyo radio states Japan has accepted the Potsdam surrender terms on August 15, 1945.

A huge crowd in New York's Times Square jubilantly welcome the news that the Japanese had accepted the Allies terms of surrender on August 14, 1945.

A huge crowd in New York’s Times Square jubilantly welcome the news that the Japanese had accepted the Allies terms of surrender on August 14, 1945.

A sailor and a nurse kiss passionately in Manhattan's Times Square, as New York City celebrates the end of World War II on August 14, 1945.

A sailor and a nurse kiss passionately in Manhattan’s Times Square, as New York City celebrates the end of World War II on August 14, 1945.

The scene aboard the battleship Missouri as the Japanese surrender documents were signed in Tokyo Bay, on September 2, 1945. Here, General Yoshijiro Umezu signs the Instrument of Surrender on behalf of the Armed Forces of Japan, Foreign Minister Mamoru Shigemitsu (behind him, in top hat) had earlier signed on behalf of the government. Both men were later tried and convicted of war crimes. Umezu died while in prison, Shigemitsu was paroled in 1950, and served in the Japanese government until his death in 1957.

The scene aboard the battleship Missouri as the Japanese surrender documents were signed in Tokyo Bay, on September 2, 1945. Here, General Yoshijiro Umezu signs the Instrument of Surrender on behalf of the Armed Forces of Japan, Foreign Minister Mamoru Shigemitsu (behind him, in top hat) had earlier signed on behalf of the government. Both men were later tried and convicted of war crimes. Umezu died while in prison, Shigemitsu was paroled in 1950, and served in the Japanese government until his death in 1957.

Dozens of F4U Corsair and F6F Hellcat fighter planes fly in formation over the USS Missouri, while the surrender ceremonies to end World War II take place aboard the U.S. Navy battleship, on September 2, 1945.

Dozens of F4U Corsair and F6F Hellcat fighter planes fly in formation over the USS Missouri, while the surrender ceremonies to end World War II take place aboard the U.S. Navy battleship, on September 2, 1945.

American servicemen and women gather in front of

American servicemen and women gather in front of “Rainbow Corner” Red Cross club in Paris, France to celebrate the unconditional surrender of the Japanese.

An allied correspondent stands in the radioactive rubble in front of the shell of a building that once was an exhibition hall in Hiroshima, Japan, one month after the first atomic bomb ever used in warfare was dropped on the city by the U.S. The explosion took place almost directly above the dome.

An allied correspondent stands in the radioactive rubble in front of the shell of a building that once was an exhibition hall in Hiroshima, Japan, one month after the first atomic bomb ever used in warfare was dropped on the city by the U.S. The explosion took place almost directly above the dome.

(Photo credit: AP Photo / U.S. Navy / USAF).