Nine thousand scientists from 43 nations signed a petition to ban nuclear testing.
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The largest US underground bomb was detonated on Amchitka Island, a remote Alaskan island.
The United States conducted its first and only nuclear artillery test at the Nevada Test Site.
North Korea performed a controversial intercontinental ballistic missile test.
British Prime Minister Winston Churchill went public that Britain had its first atomic bomb and planned to test it in Australia by the end of the year.
The United States and Russia signed the Moscow Treaty, agreeing to limit their nuclear arsenals.
