Niels Bohr presents his “Open Letter to the United Nations.” As early as 1944, Bohr had recognized that the creation of atomic weapons would completely change the nature of future warfare. Bohr stressed the free exchange of scientific and technological information as critical to creating the basis for peaceful cooperation between nations, and reflected on the "hopes and the dangers" of the Atomic Age.

The "Oak" nuclear test is conducted by the United States on June 28, 1958 at Enewetak Atoll in the Marshall Islands. It was part of the Operation Hardtack I series. The Oak Shot, conducted on a barge, yielded nearly 9 megatons, making it the 6th largest U.S. nuclear test.

The United States conducts the Coulomb-B Shot safety test during Operation Plumbbob, a controversial series of 29 nuclear tests held at the Nevada Test Site. Detonated on September 6, 1957, Coulomb-B was intended to make sure that an accidental detonation of conventional high explosives in a nuclear device would not cause a nuclear reaction.

The United States conducts Shot Priscilla on June 24, 1957. It was the third of 29 nuclear tests conducted at the Nevada Test Site in 1957 as part of Operation Plumbbob. "Priscilla" yielded 37 kilotons. Operation Plumbbob was the longest, most comprehensive test series in the continental United States and became controversial after much of the operation was declassified. Plumbbob released approximately 58,300 kilocuries of radioiodine (I-131) into the atmosphere over a four month period, producing about 32% of all civilian exposure due to continental nuclear tests.

The United States conducts the "Simon" test on April 25, 1953. It was the 7th nuclear detonation in the Operation Upshot-Knothole test series at the Nevada Test Site. It yielded 43 kilotons.