Men on motorcycles inspect a site hit by what activists said were air strikes carried out by the Russian air force in the town of Babila, in the southern countryside of Idlib, Syria. Photograph: Khalil Ashawi/Reuters

The United States will largely abandon its failed efforts to train moderate Syrian rebels fighting Islamic State, and instead provide arms and equipme(...)

US president Barack Obama points to Bear Glacier during a boat tour of the Kenai Fjords National Park in Alaska. He used the trip to press home the message that changes unfolding in the Arctic pose an urgent threat to local populations and the rest of the world. Photograph: Mandel Ngan/AFP/Getty Images

Last April, two experienced polar researchers set off from the remote Canadian outpost of Resolute Bay, planning to ski 400km across the high Arctic. (...)

Democratic presidential candidate Hillary  Clinton  appears to be behaving like she might have something to lose in her race to win the Democratic nomination. Photograph: AP Photo/Charlie Neibergall

Hillary Clinton is approaching her presidential campaign with a new abandon. She is showing a more human side by lampooning Republicans on comedy TV a(...)

 General John Campbell testifies before the Senate armed services committee in Washington, DC. The commander said the MSF hospital was “mistakenly struck” by US forces. Photograph: Jim Watson/AFP/Getty Images

US special forces, rather than their Afghan allies, called in the deadly air strike on the Médecins Sans Frontières (MSF) hospital in Kunduz, the U(...)

Army general John Campbell, commander of US forces in Afghanistan, prepares to testify for a hearing before the senate armed services committee  in Washington, on Tuesday. Photograph: Doug Mills/The New York Times

The deadly air strike that hit a hospital in the Afghan city of Kunduz was a mistake made within the US chain of command, the American commander of in(...)

Surgeons work inside a Médecins Sans Frontières (MSF) hospital after the  air strike in Kunduz, Afghanistan. Photograph: Reuters 0:51

Médecins Sans Frontières has demanded that an independent international body investigate the air strike that hit an Afghan hospital on Saturday, kill(...)

Hillary Clinton: One of the funnier emails shows her  struggling to place a call to the White House, ranting to an aide about a telephone operator. Photograph: Charlie Mahoney/New York Times.

Another month, another release of Hillary Clinton emails. The latest batch of private emails sent to and from the Democratic presidential frontrunner (...)

Dark streaks on the slopes of Hale Crater on Mars are believed to have been formed by seasonal flow of water. Photograph: EPA/Nasa/ JPL-Caltech/University of Arizona

In the Ray Bradbury short story A Sound of Thunder, a time traveller goes back to the late Cretaceous era, because who doesn’t want to see a live dino(...)

America’s latest mass shooting, which left ten people dead in Roseburg, Oregon, followed the familiar pattern of a troubled young man murdering innoce(...)

US president Barack Obama pauses as he speaks in press briefing room at the White House in Washington, while discussing the mass  shooting at the community college in Oregon. Photograph: AP

US president Barack Obama put words to the desperation of millions of Americans – and the despair of the rest of the world – on Thursday night after a(...)