One of the declassified documents outlines the chemicals and techniques necessary for developing certain types of secret writing ink and a method for opening sealed letters without detection.
Sources
- Secret Writing: CIA's Oldest Classified Documents - CIA (cia.gov)
- https://www.reuters.com/article/us-usa-cia-documents/cia-declassifies-oldest-documents-containing-secret-ink-formulas-idUSTRE73D8H020110415 (reuters.com)
- https://www.theguardian.com/world/2011/apr/17/cia-declassifies-oldest-documents-secret-ink (theguardian.com)
- https://www.nbcnews.com/id/wbna42630961 (nbcnews.com)
More in History
- Apollo astronauts had to perform some return maneuvers while their spacecraft was behind the moon and outside communications range with Earth.
- The July 2025 National Archives release included State Department records concerning James Earl Ray's extradition from the United Kingdom.
- The Classis Pontica was a Roman provincial fleet.
- The first public release of translated VENONA messages occurred in July 1995 and contained 49 messages concerning Soviet attempts to obtain information about U.S. atomic-bomb research and the Manhattan Project.
- In the 1980s, the U.S. military was restricted to providing no more than 55 advisors to El Salvador's government in its fight against the Farabundo Martí National Liberation Front insurgents.
- National Liberation Front commandos blasted through the wall surrounding the American embassy in Saigon during the Tet Offensive and unsuccessfully attempted to seize the embassy building.