Manhattan Project Secrecy

On Facebook this month we're going #InsideTheArchives to explore Manhattan Project secrecy.

A military examiner, identified only as #2034, used these two censor form slips to return a letter to Edward Wilder. Wilder Collection, Los Alamos Historical Society Archives and Collections.

During the Manhattan Project in Los Alamos, large posters featuring sayings such as “What you see here, what you do here, what you hear here, when you leave here, let it stay here” were prevalent to remind personnel of the importance of secrecy. The daily lives of the folks in Los Alamos were affected by security measures. All letters coming out of Los Alamos were checked by the military and if they were found to be in violation of Project security, they were returned to the sender. We’re sharing some of the examples we have #InsideTheArchives of the censorship that happened in Los Alamos.

For more interesting stories about censorship on “The Hill” during World War II, visit the Voices of the Manhattan Project website and listen to interviews by Pat Krikorian or Bob Carter to hear first-hand accounts of their experiences.