World War II saw the development and use of many new types of weapons, but none were nearly as powerful as the atomic bomb. The bomb came to be as the result of a top-secret joint effort between America and the United Kingdom, the goal of which was to build an atomic bomb that could be used against Germany. This program, later known as the Manhattan Project, was run by General Leslie R. Groves at locations such as Los Alamos, New Mexico and was fully known only to a handful of scientists and politicians. The Manhattan Project led to the construction of four atomic bombs, two of which were detonated over Japan in August of 1945.

The decision to detonate the bombs over Japan came with much controversy. The creators of the bomb were among those who argued, on moral, humanitarian and practical grounds, that it should not be used against a prostrate if unyielding Japan. However, there was a great deal of pressure on US President Harry Truman to give the go ahead to drop the bombs. He was convinced by Secretary of War Henry Stimson and his advisors that the dropping of the atomic bombs would be a solely military action that would avoid the loss of as many as a million lives in the upcoming invasion of the island of Kyushu. He was also pressured by domestic tensions, issues of reelection, and a collective American feeling of hatred toward the Japanese race. Thus, only a few weeks after becoming President, he gave the go ahead to detonate the atomic bombs over Japan.

The city of Hiroshima was chosen as the target for the first atomic bomb to be used against an opposing nation. Hiroshima, a medium-size city beside Japan's inland sea, was chosen because it had large military and supply bases, shipyards and industrial plants. Its population of 380 000 had been reduced to less than 300 000 through evacuation and the demolition of about 70 000 homes to create firebreaks, but its centre was still densely populated and it had so far escaped serious damage from conventional bombing.

Two bomber crews and their back-up teams begain training in America in the summer of 1944. They were not told exactly what they were training for. Out of these bomber crews, Colonol Paul W. Tibbets formed the self-contained 509th Composite Group (known simply as the 509th), which moved to the island of Tinian in May of 1945. The 509th flew practise missions against the major Japanese bases on Truk island, dropping ten thousand pound TNT-filled, orange-painted bombs nicknamed "Pumpkins" because of their shape and colour.

Two atomic bombs joined the 509th on Tinian as they were carefully shipped, in pieces, from the United States mainland in July of 1945, where they were assembled and made ready to drop. The first bomb contained uranium and was twenty-eight inches in diamater, twelve feet long and weighed about nine thousand pounds. Because it was considerably smaller than the second bomb, it was nicknamed "Little Boy". The second bomb was based on a different principle using plutonium and was five feet in diameter, almost eleven feet long and weighed about ten thousand pounds. It was much larger than "Little Boy," and thus earned the nickname "Fat Man".

As August came, all of the necessary preparations had been made and "Little Boy" was ready to drop. After five days of unsuitable weather, Colonol Tibbets and his crew took off at 2:45 AM Tinian time on August 6th for a 13 hour round trip to Japan in the plane which he had named the "Enola Gay," after his mother. As the plane neared Hiroshima and was at an altitude of about 4700 feet, Captain William S. Parsons descended into the bomb bay to arm "Little Boy". After passing Iwo Jima, the bomber cruised at around 9200 feet for most of the flight and then climbed to 31 060 feet to make the bombing run. By 8:15 AM Japan time the bombardier, Major Thomas W. Ferebee, had the Aioi Bridge aiming point in his sights, and released the bomb.

It took 43 seconds for the bomb to reach the point of explosion and at 8:16 AM, when it reached an altitude of 1900 feet, it exploded with a blinding flash of light intense enough to expose film inside cameras. One of the crewmen of the Enola Gay described what he saw of the blast as "a peep into hell". Another later asked himself in his diary "My God, what have we done?". In an instant, the bomb had left ten square kilometres of Hiroshima's busy industrial, commercial and residential centre a flattened wasteland. The blast was later esitmated as equivalent to 12 700 tonnes of TNT and the ground temperature immediately beneath the explosion was later estimated to be at least 5000°C, causing thousands of people to be instantly vaporised. The blast tore skin and clothing from others farther from the epicentre, and the shock wave flattened office blocks, factories and homes, leaving thousands more buried under blazing rubble. Tramcars flew through the air, trains were up-ended and the grass and trees of parklands blazed like dry kindling.

Overturned charcoal cooking stoves fuelled fires that raged through the city, blown by a fierce whirlwind. Many who sought refuge in the river were drowned as powerful winds whipped up high waves. Soon, black raindrops as large as marbles began to fall - vaporized moisture from the fireball condensing as a vast mushroom-shaped cloud rose above it and cooled. They carried the deadly, silent radiation that would claim many more victims. Thousands of severely injured people swarmed the hospitals where very few doctors were still healthy enough to assist them. Many people died while laying in the hallways of hospitals waiting for their injuries to be tended to. The days in Hiroshima after the explosion were chaotic and those that had less minor injuries seemed to be the unfortunate ones as they took it upon themselves to help as many people as they could, often without getting any sleep at all for several days.

Nobody in Hiroshima knew what had happened to cause such destruction. Many believed that it had not been a bomb at all, but was a kind of fine magnesium powder that had been sprayed over the city by a single plane and exploded when it came into contact with the live wires of the city's power system. Others believed that it had been a plane which had poured a large amount of gasoline onto the city which was somehow ignited. These theories were soon put to rest when the Japanese Emperor Hirohito addressed the people of Hiroshima by radio and explained, to the best of his knowledge, what had happened.

About four days after the explosion, many people began to show signs of radiation sickness. Wounds would partly heal and then open back up, many people lost their hair, many more people became severely ill and others began to notice strange spots appearing on their flesh. Many of these people would die within two weeks.

The atomic bomb dropped on Hiroshima had widespread and long-lasting effects on the city. About 62 000 of the citiy's 90 000 buildings were destroyed and 6000 more were damaged beyond repair. It also left behind many smaller reminders of just how powerful it was. It melted cans and bottles 80 yards from the center, charred telephone poles 4400 yards from the center and melted clay at 1300°C 600 yards from the center. It was estimated that the pressure exerted by the explosion varied from 5.3 to 8.0 tonnes per square yard, enough to level buildings leaving no evidence that they were even there. The intense flash of the explosion left shadows of trees or people permanently imprinted on walls all over the city and many of the city's clocks were forever stopped at 8:16 AM.

Shortly after the bomb was dropped, hundreds of scientists swarmed into Hiroshima to learn of its effects. It was estimated that, in all, over 100 000 people had been killed. 25% were killed from direct burns, 50% from other injuries and 25% from radiation effects. It was hoped that such a demonstration of power would lead to a Japanese surrender and the end of the war, but no Japanese surrender was forthcoming. The United States then did something which, to this day, is questioned for it's necessity. On August 9th, 1945, they dropped the second atomic bomb, "Fat Man," on the major military port and shipbuilding centre of Nagasaki. "Fat Man" contained plutonium and was much more powerful than "Little Boy," which contained uranium and was dropped on Hiroshima.

Major Charles W. Sweeney took off at about 3:45 AM Tinian time with "Fat Man" on board, destined for Kokura in a borrowed B-29 called Bockscar, named for its original commander. This flight was to be plagued with problems. Just before takeoff, it was discovered that the plane had a faulty fuel pump, but it was too late to delay the mission, so about 2730 litres of fuel in an auxillary tank could not be used. When Sweeney reached the southern island of Yakoshima, where Bockscar was to rendezvous with two observation aircraft, one of them failed to arrive on time. The B-29 circled for about fifteen minutes, then Sweeney headed for the primary target, Kokura, at the northern tip of Kyushu, with its huge military arsenal. But heavy cloud over Kokura ruled out visual bombing, which had been ordered. After three abortive runs, using even more precious fuel, Bockscar headed south-west 160 km for the secondary target, Nagasaki. There Sweeney found a break in the cloud and dropped the bomb at 11:01 AM from an altitude of 28 900 feet. He then headed for Okinawa, rather than far-distant Iwo Jima as planned, on his little remaining fuel.

An alert sounded in Nagasaki five minutes before "Fat Man" fell, but few people bothered to seek Nagasaki's ample hillside shelters. The bomb exploded about 1650 feet over the industrial and resedential district of Urkami, smashing and sprawling Mitsubishi works. Despite its great power, the bomb caused less damage than "Little Boy" had at Hiroshima, because hills around and within the city contained the blast. Nonetheless, the bomb flattened the northern part of Nagasaki and killed 35 000 people according to US estimates, although the Japanese later put the toll at 87 000.

There were horror scenes similar to those in Hiroshima, but expanses of water prevented a firestorm. Damage extended over a roughly oval area 4 by 2 km at its widest, in which virtually every building was demolished or rendered uninhabitable. But the city was not as congested as Hiroshima and emergency services were not as seriously hampered.

The message that a new dimension in devastation had arrived was not lost on Japan's rulers. On the same day as the Nagasaki strike, the Soviet Union invaded Machruia and the combination provided the shock needed to turn the divided Japanese government towards peace. Emperor Hirohito and his peace-inclinded ministers had been convinced by the enormous displays of devestation that had been unleashed upon them that there was no option but to accept American surrender terms. In this sense, the bombs had justified their development and use. They had been dropped primarily to knock Japan out of the war and prevent Allied casualties - a million according to one estimate - which would have inevitably followed an invasion of Japan.

The power demonstrated by the bombings of Hiroshima and Nagasaki left Japan with no choice but to surrender or be wiped off the map with a full-scale atomic raid. Japan didn't know it at the time, but America had no more atomic bombs immediately available, and their threats of destroying Japan were empty. However, Japan didn't take any chances and they began surrender negotiations with America within hours of the Nagasaki explosion. Word War II was over, and it was the atomic bombs that were dropped on Hiroshima and Nagasaki that had ended it.

There are still many people who dispute whether or not the use of the atomic bombs was too high a price to pay for peace. It has been concluded that approximately 270 000 citizens of Hiroshima and 87 000 citizens of Nagasaki had either been killed outright or had died of radiation sickness within five years of the dropping of the bombs. US President Harry Truman originally made the decision to use the bombs because it was supposed to save more lives than it would take. However, we cannot know for sure if his plan succeeded and if the use of the bombs did in fact take fewer lives than an invasion of Japan would have. But with that kind of devestation and with approximately 360 000 people killed, the vast majority of which were civilians, it seems unlikely that the use of the atomic bombs in fact saved many lives. Hiroshima and Nagasaki, although rebuilt since their destruction, still carry the scars left behind by the bombs. They represent a horrific point in history and remind us of the staggering cost war brings with it.