In 1971, after the devastating 800,000-gallon oil spill in the San Francisco Bay, John Francis, then a young man, pledged to never ride a motorized vehicle again. Two years later, he added voluntary silence to his vow, spending 17 years in silence as he walked the world and became known as The Planetwalker. The first words that he spoke again were in Washington, D.C., on the 20th anniversary of Earth Day. In 2009, Francis, by then a National Geographic fellow with a Ph.D, told his remarkable story in the candid and deeply inspirational Planetwalker: 22 Years of Walking. 17 Years of Silence.
