Following six classic albums in a six year span Stevie Wonder took a three year break before releasing 1979's Journey Through the Secret Life of Plants, a largely synthesizer-heavy instrumental album which doubled as the soundtrack/score for Walon Green's environmental documentary, based on the book of the same name by Peter Tompkins and Christopher Bird. Home to standouts like "Send One Your Love" and "Outside My Window," the singular collection peaked at No. 4 on the Billboard 200 and R&B album charts. The Motown legend has called it "an experimental project with me scoring and doing other things I like: challenging myself with all the things that entered my mind from the Venus Flytrap to Earth's creation to coming back as a flower."