The Beatles classic songs 'YESTERDAY', 'Let It Be' and 'A Day in the Life' are some of the most iconic songs of all time. 'YESTERDAY' was written by Paul McCartney and released in 1965, becoming one of the most covered songs in history. 'Let It Be' was released in 1970 and is considered to be one of the band's most popular songs. 'A Day in the Life' was released in 1967 and is known for its innovative structure and production. All three songs have become timeless classics and remain popular today.