Man walks the Earth and does not speak for 17 years

I really enjoy Ted talks and this one is very special... http://www.ted.com/index.php/talks/john_francis_walks_the_earth.html.

This guy witnessed a massive oil spill in the San Francisco Bay in the 1970s and was so appalled that he gave up petrol power transport and just walked. He also gave up talking for 17 years. He realised he didn't listen enough and through not speaking he was able to learn more - as well as teach and get a PhD.

Inspirational. Reminded me of the PCT hike and the people I met doing that. There is something about people who walk long distance.