Their words and their tune have taken on special significance in American culture. Hearing Simon sing "The Sound of Silence" on the 10th anniversary of the 9/11 attacks, NBC newsman Tom Brokaw briefly struggled for composure. The music, he said, evokes memories.This is the kind of impact the library was looking to preserve, "to celebrate the richness and variety of our audio heritage," said Librarian of Congress James Billington in announcing the selections. The recording that received the highest number of public nominations for this year's registry was Pink Floyd's "The Dark Side of the Moon." The library said it was notable as an example of "brilliant, innovative production in service of the music." Other selections included the original 1949 cast album for "South Pacific" and the soundtrack to the popular 1977 movie "Saturday Night Fever," starring John Travolta and featuring the Bee Gees, which revived the disco craze. The selections span from 1918 to 1980 and represent nearly every musical and recording category. Recordings by Will Rogers, Jimmie Davis and President Dwight D. Eisenhower capture part of the political climate of their eras. In 1931, Rogers' radio broadcast at a low point in the Great Depression included a folksy chat with President Herbert Hoover to kick off a nationwide unemployment relief campaign. Davis' 1940 recording of "You Are My Sunshine" became his election campaign theme song while running for governor of Louisiana. It became one of the most popular country songs of all time and the state song of Louisiana in 1977. Eisenhower's voice was carried in a prerecorded message in 1958 by the first communications satellite launched on a U.S. rocket. Eisenhower's message of peace to the world transmitted from space was touted as a victory in the space race after the Soviet Union launched a satellite the year before.