Marvin Gaye and Tammi Terrell made Ain't No Mountain High Enough a hit for Motown in 1967.
Diana Ross followed suit in 1970 as a solo artist with her version of the song.
It has a place in people's hearts with its anthemic themes of love, loyalty, triumph and perseverance.
Cynthia Dagnal-Miron is an African American who grew up in the 1960s and she says the song gave black people a sense of comfort and of being loved.
Kevin Patterson recalls meeting an elderly lady in a store in Philadelphia and hearing the song. He learned she had been part of a movement to desegregate a local school in the 1960s and she had sung it then at a talent show.
John Harris says music and being part of a choir were what saved him when he sank into drug addiction and crime and ended up in court. When he got clean he sang that song at the Court's 25th anniversary celebration.
"No wind no rain no winters cold can stop me from getting to you" were the words Lesley Pearl sang to her birth mother as she lay gravely ill in hospital. Lesley had braved Hurricane Sandy to fly to Charleston to be with her and it brought them closer towards the end of her life.
At the height of the pandemic in 2020 when New York was suffering huge numbers of Covid deaths and hospitalisations, nurse Kym Villamer sang it to staff and patients at the hospital where she works to remind them of the perseverance of the human spirit and the goodness of humanity.
An Assistant Professor of Music at Washington University in St Louis breaks down the various musical elements that make it such an enduring powerful uplifting anthem.
Series about pieces of music with a powerful emotional impact.
Producer: Maggie Ayre
First broadcast on BBC Radio 4 in November 2021.