Forty years after the Challenger disaster, NPR explores the engineers' last-minute efforts to stop the launch, their decades of guilt and the vital lessons that remain critical for NASA today.

Russian strikes left much of Kyiv without heat, water and power during freezing temperature, even as Ukraine, Russia and the U.S. held talks on ending the nearly four-year war.

After President Trump's upheaval at Davos, U.S. allies are openly questioning whether Washington can still anchor the rules-based order.

Federal immigration officers shot and killed a U.S. citizen on Saturday in Minneapolis, drawing hundreds of protesters in a city already shaken by another fatal shooting earlier this month. DHS says the man was armed and "violently resisted" arrest but refused to answer further questions.

A look at the extreme winter storm impacting two-thirds of the U.S.

Reaction from Minneapolis Emergency Management Director Rachel Sayre to Saturday's shooting and the subsequent street confrontations.

The incident, which was caught on video, marks the second deadly shooting by federal officers in Minneapolis in less than a month.

Federal agents have shot and killed another person in Minneapolis, this time a 51-year-old man.

The announcement is a reversal for Trump, who initially initially praised the agreement with China as something Canadian Prime Minister Mark Carney "should be doing."

Dozens were killed and hundreds homes destroyed, according to the country's disaster management authority, in storms impacting 15 of Afghanistan's 34 provinces.