The last 340 hours of secretly recorded phone calls and meetings from President Richard Nixon's White House has been released.
The Nixon Library and Museum in suburban Los Angeles says the final installment covers the period from April 9 to July 12, 1973, the day before the existence of the covert recording system was revealed to a Senate committee probing the Watergate Scandal.
The tapes include discussions about several issues, including Watergate, Vietnam and the 1972 summit between President Nixon and Soviet leader Leonid Brezhnev.
Political figures on the tapes include George H.W.Bush, Ronald Reagan, Gerald Ford, Alexander Haig and Henry Kissinger.
The tapes also include excerpts from meetings and calls with heads of state, including Haile Selassie of Ethiopia, Giulio Andreotti of Italy, Willy Brandt of Germany and Pierre Trudeau of Canada.
The library also opened more than 140,000 pages of text materials.
The recordings cap the release of 3,000 hours of tapes recorded between February 1971 and July 1973.
The second Nixon term was quickly overrun by the Watergate scandal, which began in 1972 when burglars tied to his re-election committee broke into the Democratic headquarters to try to get embarrassing information on political adversaries.
The recordings cover a period that includes the resignation of two top White House staffers and the attorney general in one day, the appointment of a special Watergate prosecutor and the formation of a Senate committee that would hear damning Watergate testimony.
Faced with impeachment and a possible criminal indictment, Nixon resigned on August 9, 1974, a little more than a year after the tapes end. He was pardoned a month later by then-President Gerald Ford.
Another 700 hours of Nixon White House tapes remain classified or restricted because of national security and privacy concerns.