The Manhattan project helped to end the war by creating the atomic bomb.
This secret government project funded by the US government resulted in the best and brightest scientists working on the creation of the atomic bomb. This type of weapon had never been used before in world history. However, at the end of World War II, the US would use this bomb twice. One would be used on Hiroshima and the other used on Nagasaki. The use of the atomic bomb on both of these cities resulted in the unconditional surrender of Japan, officially bringing an end to World War II.