July 16: Atomic Era begins with the Manhattan Project in 1945, when the United States successfully explodes a plutonium bomb in New Mexico.

The Manhattan Project created the first nuclear bombs. The test of "Trinity" pump is shown in the photograph.

"Trinity" was the name assigned to the explosion of the first nuclear device on July 16, 1945, as a result of the Manhattan Project.

"Little Boy", left, explodes over Hiroshima on August 6, 1945, and "Fat Man", right, explodes over Nagasaki on 9 August.

British and American researchers began to search the feasibility of nuclear weapons since 1939. The practical tests began in 1942 when efforts were transferred to the US Army and turned into the famous "Manhattan Project."

Silverplate B-29 Straight Flush.The tail code of the 444^th Bombardment Group is painted on for security reasons.

The development of weapons took place at Los Alamos Laboratory in New Mexico. The code name for the first blast was "Trinity" that used a plutonium implosion design which they called "The Gadget".

President Harry S. Truman  signs the Atomic Energy Act of 1946  establishing the United States Atomic Energy Commission. 

The same device was used for the second atomic bomb dropped on Japan in Nagasaki, killing more than 70,000 civilians and with disfiguring radiation affecting the rest of the city population. Japan did not want to accept unconditional surrender.

The United States Government proposed the Soviet Union to help find the Japanese surrender, but the Soviets saw an opportunity to seize the Pacific ...thus USA anticipated and became the first successful experiments.


The Declaration of Potsdam (Berlin) was the declaration signed by US President Harry S. Truman, British Prime Minister Winston Churchill and Chiang Kai-shek, chairman of the Nationalist Republic of China in 1945. The Declaration called on the Japanese Empire to give up war.

The political and cultural impacts of the development of nuclear weapons were profound and far-reaching.