14231337_10155239453374966_3845707010656425530_o#3 – Marvin Gaye & Tammi Terrell – “Ain’t No Mountain High Enough” – (1967)

This might be the best “Motown” song (even though technically it was released on Tamla label, which is what Motown was called first). Marvin Gaye had a lot of duet hits in the 1960s and did an entire album with Tammi Terrell. It’s been covered a lot (and Diana Ross took it to #1) but this is and always will be the best version. Fun fact: this song was written by Ashford & Simpson who would have their own success about a dozen years later.