A duck leaves a clear trail as it swims through algae-covered waters in Sydney—but the duck isn’t the only "green" lover in this bustling city. Laborers working on Sydney's famed opera house refused to build an underground parking garage next door for fear of killing three historic fig trees in the Botanic Gardens.

(Text adapted from and photograph shot on assignment for, but not published in, "Sydney," February 1979, National Geographic magazine)