There was a rumor in the Soviet Union that The Beatles had secretly visited the U.S.S.R. and given a private concert for the children of top Communist party members. They believed the song "Back In The U.S.S.R." was written because of the concert. Actually, some fans still believe so.
"(What's So Funny 'Bout) Peace, Love, and Understanding" was written by Nick Lowe in 1974. The original version with his group Brinsley Schwarz was kind of somber, but Elvis Costello made it a classic with his 1978 uptempo take.