The following websites provide access to many of the NSA documents leaked by Edward Snowden beginning in 2013. Many of these documents are not yet declassified.
The following websites provide access to documents published by WikiLeaks. Many of these documents are not yet declassified.
The Pentagon Papers, officially titled "Report of the Office of the Secretary of Defense Vietnam Task Force", was commissioned by Secretary of Defense Robert McNamara in 1967.
This classified report was leaked to the media in 1971 by Daniel Ellsberg. It was finally declassified in 2011, when the National Archives and Records Administration released the complete text of the report for the first time.