Simon & Garfunkel song preserved at Library of Congress
Simon & Garfunkel's song The Sound of Silence has become one of 25 recordings to be preserved in the US Library of Congress National Recording Registry.
Written after President John F Kennedy was assassinated, the song's success prompted the split duo to re-form.
Alongside 1960s dance hit The Twist by Chubby Checker, it is among several songs selected by the library for their cultural and artistic significance.
Spanning from 1918-1980, the recordings include audio from US presidents.
Garfunkel, 71, told the Associated Press that he had hoped his performances would have enduring appeal.
He recalled thinking in the 1960s: "If we do really good and give a very special performance to these great Paul Simon songs, we might last right into the next century and be appreciated."'Celebrating variety'
James Billington, Librarian of Congress, said the purpose was to choose sounds that have acquired a special significance in American culture "to celebrate the richness and variety of our audio heritage".
Pink Floyd's The Dark Side of the Moon received the most public nominations for this year's registry.
The soundtrack for the 1977 film Saturday Night Fever, and the original cast album for the musical South Pacific from 1949 were among the other tracks selected.
A 1940 Jimmie Davis recording of You Are My Sunshine - which is one of the most popular country music hits ever and became Louisiana's state song in 1977 - was also added to the registry.
A 1931 radio broadcast of a folksy chat between entertainer Will Rogers and President Herbert Hoover, about an unemployment-relief campaign, was among the non-musical audio added.
A message from President Dwight Eisenhower, recorded in 1958, that was carried by the first US communications satellite and broadcast from space was included.
The registry also chose the recording of American pianist Van Cliburn playing in Moscow in 1958 when he won the Tchaikovsky International Piano Competition at the age of 23.
The Library of Congress is engaged in a programme to help libraries and archives preserve recorded sound, and guard against losing key recordings.