Video: Alexandra Cousteau ventures out of sight, deep into the cool world of New Mammoth Cave in Tennessee. |
Video: On the Rachel Maddow Show, congressional candidate Art Robinson, R-Ore., talks about the smear campaign against him regarding his scientific studies. |
Video: The National Landscape Conservation System celebrates a decade of protecting treasures in America's wild West. |
Video: A waste reservoir at an alumina plant in Hungary burst on Tuesday, unleashing a river of red chemical sludge, and leaving four people dead and another six still missing. |
Video: An airport in inner Mongolia reportedly shut down due to UFO sightings. |
Mark Ruffalo, actor and environmental activist whose family lives in an area of upstate New York directly where 'fracking' is a common practice, explains the dangers to MSNBC's Rachel Maddow. |
Video: Dean Corren's vision of a greener world includes using New York City's East River to produce electricity. As technology director at Verdant Power, he's trying to make it happen with underwater turbines. |
Video: Officers say they thought the dog was a threat, but the Oakland, Calif., family wonders if the officers could have used less than lethal force. |
Video: With a story similar to "Avatar," film director James Cameron now finds himself on the side of native people in Canada's oil sands region, where their way of life is threatened by oil exploration and mining. |
