U.S.

"There's something about waves that can get you into kind of a mental funk," one philosopher says. For NPR's summer science series, Joe Palca tries to answer the big question: What is a wave?

It's an ongoing standoff between musicians and Google's YouTube: Who should be responsible for removing unauthorized copies of songs posted online?

Donald Trump laid out his economic policies during a speech in Detroit Monday.

Thousands of travelers were stranded at airports around the country Monday morning when a computer system outage grounded all Delta Air Lines flights. Operations have now resumed, but hundreds of flights are still delayed and many more were cancelled. It may take several days before Delta's flight operations return to normal.

Hillary Clinton began a two-day campaign visit to the key battleground state of Florida on Monday.

To international foodies, the Rocas are rock stars of haute cuisine. This summer, they've bolted their restaurant in Spain to cook gourmet pop-up meals in five cities over five weeks.

New Hampshire's attorney general claims five drug companies are stifling an investigation into how they market opioids. The allegations are the latest in a string of legal actions that aim to hold drug companies accountable for a spike in opioid abuse.