In 1971, Francis witnessed two tankers collide beneath the Golden Gate Bridge, spilling more than half a million gallons of oil into the bay, and he had a strange thought: What would happen if people stopped using cars? For the next 22 years Francis refused to ride in motorized vehicles, and for 17 of those years he took a vow of silence. During his silence, Francis reconnected with nature and completed three college degrees, culminating in a Ph.D. in land management. Francis also wrote the inspiring book “Planetwalker” and created an earth-stewardship group known as Planetwalk. Francis has also been employed by the Coast Guard where he has worked on oil spill legislation, and in 1991 he was named a UN Environmental Program Goodwill ambassador.