Ski mountaineering will make its Olympic debut this year, the first winter sport to do so since 2002. Skeleton, luge, ski jumping and moguls are also getting new events.

As Nigeria battles multiple security crises, a single attack in the west left more than 160 people dead and raises new questions about who's really in control.

President Trump's focus overseas may spare China for now, but Beijing still worries that his "America First" rhetoric hasn't softened what it calls U.S. "military adventurism."

Until now, estimating how old a dinosaur was when it died has been a fairly simple process: Count up the growth rings in the fossilized bones. But new research into some of dinosaurs' living relatives, like crocodiles, suggests that this method may not always work.

A month after Maduro's ousting, Venezuela's Interim leader walks a tightrope between US demands and Chavista hardliners' expectations.

Are the world's superpowers back in an arms race now that the new START treaty has expired? NPR's Leila Fadel speaks with arms control expert Rose Gottemoeller.

The last major arms control treaty between Russia and the U.S. will expire on Thursday.

In Kyiv, dance parties on a frozen river keep spirits -- and bodies -- warm after Russian strikes shattered Ukraine's energy grid.

A young French tennis coach who once lived the American dream describes being detained, shackled and expelled under the Trump administration's tightened border rules.

Relatives of two Trinidadian men killed in a U.S. airstrike last year are suing over what they call extrajudicial killings. It's the first such case to land in an American courthouse.