John Francis is an environmentalist, educator, conservationist, and author. In 1971 he witnessed the collision of two Standard Oil tankers in San Francisco Bay. Soon after he vowed to never ride or drive a motorized vehicle again in protest of the environmental harm caused by fossil fuels. For the next 22 years Francis walked wherever he needed to go. This earned him the nickname “Planetwalker.” Two years after the tanker incident, Francis also gave up speaking—-a pledge of silence that lasted 17 years.