Charlie Chaplin wrote the music for 'Smile' in 1935 for the film 'Modern Times', but the lyrics were only added nearly 30 years later.
Chris Philips tells the story of how his grandfather was inspired to write the words when he left his father at boarding school.
Gemma Lowery talks about how her son Bradley loved the song.
Writer Bryony Rheam describes why she associates the song with her grandmother.
Marine Lucas remembers flying to Michael Jackson's memorial on hearing the news of his death.
And author Bob Williams remembers when his father died, how his mother sat on the floor listening to the Nat King Cole version - crying when he came home from school.
Series about pieces of music with a powerful emotional impact.
Producer: Sara Conkey
First broadcast on BBC Radio 4 in January 2019.