Germany surrendered because of invasion from Allies. The Soviet Union Surrounded Berlin, Germany's capital. The Americans, coming from the west linked up with the Soviets. This combined force proved to be to much for Germany's weekend army to handle. After his bunker was surrounded Hitler killed himself and shortly there after Germany surrendered.
The relationship between the United States and the Soviet Union has changed very much since World War 2. During the war, we were allies and due to each other we were able to bring down the Germans. However, after the war our relationship with the Soviet Union quickly deteriorated and now we are enemies. I believe in the modern age the Soviet Union is without a doubt foe, however during the war, they were friend.
The Manhattan Project was the code name for the the US governments development of the atomic bomb. Atomic bombs are bombs powered by the splitting of atoms. They are extremely powerful and deadly weapons. The bombs that we developed during the Manhattan Project ended up ending the war.
Hiroshima was the first city in the world to ever be bombed with an atomic bomb. It was also bombed before Nagasaki. Hiroshima was chosen because of its important military base. It was also chosen because it hadn't been bombed by the normal bombing raids.
Nagasaki was the second city to ever be bombed with an atomic bomb. It was also the second city bombed with an atomic bomb in Japan. After the bombing Japan unconditional surrendered. Nagasaki was not a primary target due to its hilly terrain but weather forced it to be bombed.
Japan surrendered because they had exhausted all of the military might. An invasion was inanimate. The two atomic bombs just sealed the deal. Japans unconditional surrender ending World War 2.