A study shows that preserving just four percent of the world's oceans could be crucial in preserving marine mammal species. Is private ownership the key?

New data indicates the continuation of a long-term decline in summer ice underway since at least 1979. Researchers say roughly half the decline can be attributed to global warming.

After days of upheaval, the troops of Operation Hammer Down finally got their bearings before the mission ended. But afterward they wondered, did they accomplish anything?

AP - Ten years on, Americans come together Sunday where the World Trade Center soared, where the Pentagon stands as a fortress once breached, where United Airlines Flight 93 knifed into the earth.

AP - Ten years on from the day the 9/11 terrorist attacks changed so much for so many people, the world's leaders and millions of citizens are pausing to reflect.

AP - U.S. intelligence agencies have found no evidence that al-Qaida has sneaked any terrorists into the country for a strike coinciding with the 10th anniversary of the Sept. 11 attacks, senior officials said Saturday.