TED Radio Hour http://apr.org en Are Earth's Deepest Caves The Last Frontier? http://apr.org/post/are-earths-deepest-caves-last-frontier <em>Part 2 of the</em> TED Radio Hour <em>episode</em> <a href="http://www.npr.org/2013/07/11/201092483/to-the-edge" target="_blank">To The Edge</a>.<p><strong>About Bill Stone's TEDTalk</strong><p>Bill Stone is a maverick cave explorer who has plumbed Earth's deepest abysses. Fri, 26 Jul 2013 13:42:00 +0000 editor 34868 at http://apr.org Are Earth's Deepest Caves The Last Frontier? To The Edge http://apr.org/post/edge <blockquote><em>"Certainly to enter a world of terror, you should not be pushed by someone. You should be called. You should be curious. You should have the heart of an explorer."</em> — Philippe Petit, high-wire artist<p></blockquote><p>Some people might only dream of adventure, but for others, there's no option but to explore the most extreme places on Earth. From the deepest caves to the roughest oceans, from the North Pole to dizzying heights on a high wire — what drives adventurers to constantly push themselves to the brink of human endurance? Fri, 26 Jul 2013 13:41:00 +0000 NPR 34866 at http://apr.org To The Edge