cover-up
attempt to conceal evidence of wrongdoing or failures
Operation Legacy
British program to prevent sensitive documents from being inherited by its ex-colonies
Roswell incident
1947 unspecified object crash near Corona, New Mexico, US
American cover-up of Japanese war crimes
after Japan's surrender in World War II, the United States gave immunity from prosecution to members of Unit 731 and withheld relevant information in exchange for their human experimentation research