"Because I didn't speak, everyone paid attention," John Francis told AP's Marcus Wohlsen.
Francis, now 61 years old, drives a Prius, flies more than 100,000 miles a year giving inspirational speeches. He earned three degrees, including a doctorate in environmental studies, during his non-speaking days.
Francis gave up cars after an an oil spill near the Golden Gate Bridge. When he was hit by a car, he walked to the hospital rather than use gasoline power. He stopped talking in 1973 and didn't speak again until Earth Day 1990. He admits falling off the wagon a couple times, such as when he told his parents he loved them.
We may see more of Francis on the silver screen. A Hollywood producer gave him a Prius after optioning the rights to make a movie based on his memoirs, a 2005 book called "Planetwalker."
[Source: Marcus Wohlsen / Associated Press via North County Times]