A remarkable film from the National Geographic's daring EXPLORER series, ICELAND RIVER CHALLENGE follows twelve modern-day pioneers on a treacherous expedition down a remote Icelandic river. Crash through waterfalls and glide through sparkling glacial tunnels on this breathtaking journey. Using kayaks, inflatable rafts, and ultralight aircraft, the adventurers journey through the beauty and isolation of this dangerous waterway. Come explore a river that has, until now, defied exploration; witness the heart-stopping power of nature in all its glory with ICELAND RIVER CHALLENGE.

Iceland's Eyjafjallajokull volcano erupted April 14, 2010, spewing aircraft-harming ash over most of Europe. It could cause Katla, its neighboring, larger volcano to erupt. NGC looks at Eyjafjallajokull before, during and after, explaining the science behind the chaos and the biggest disruption of air traffic since 9/11.