As the Apple Watch goes on sale Friday, it's unclear if the gadget and others like it can attain the utility and prominence smartphones have in the past eight years. Ryan Emberley/AP hide caption

itoggle caption Ryan Emberley/AP

Rida Sihab Mansour, a staff sergeant in the National Guard, stands with the uniform he wears when he serves on the honor guard at military funerals. He says he's positive that his guard commitments are making it more difficult to build a career. Katie Schoolov/KPBS hide caption

itoggle caption Katie Schoolov/KPBS

"There are two ways to go forward from here, and history shows this," Martin O'Malley said of the two parties' approaches to fixing the economy. "One path is a sensible rebalancing that calls us back to our tried and true success story as the land of opportunity. The other is pitchforks." Ariel Zambelich/NPR hide caption

itoggle caption Ariel Zambelich/NPR

In the 1950s, the World Bank funded the creation of the world's largest man-made dam, the Kariba Dam, which sits on the border of Zimbabwe and Zambia. The construction of such dams can have dire consequences for poor people living near a river, an investigation found. Jekesai Njikizana/AFP/Getty Images hide caption

itoggle caption Jekesai Njikizana/AFP/Getty Images

At the Pelican Hill golf resort in Newport Coast, Calif., water conservation is an obsession. Yuki Shimazu/Flickr hide caption

itoggle caption Yuki Shimazu/Flickr

As China continues its massive economic growth, especially in cities, the government continues to severely limit people's rights. Is that system sustainable? Johannes Eisele/AFP/Getty Images hide caption

itoggle caption Johannes Eisele/AFP/Getty Images

Students at the Pennsylvania College of Technology are learning a technique called "tripping pipe," moving a pipe from a stack into a horizontal position and lowering it down into a well. The students train on a practice drilling rig to learn how to be roustabouts. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

In 22 states, people who default on their student loans can have professional licenses suspended or revoked. The percentage of Americans who default on student loans has more than doubled since 2003. Butch Dill/AP hide caption

itoggle caption Butch Dill/AP

More Americans are ditching traditional cash and plastic, opting instead for new mobile payment applications. But new research indicates cash isn't completely dead. Amy Sancetta/AP hide caption

itoggle caption Amy Sancetta/AP

Jessey Drewsen, 25, lives near the H Street Wal-Mart in Washington, D.C. She says she doesn't like the store, but that she goes there for cheap supplies like pens. Emily Jan/NPR hide caption

itoggle caption Emily Jan/NPR

The H Street Wal-Mart in Washington, D.C. Ten years ago, none of the city's 600,000 residents lived within 1 mile of a Wal-Mart. Today, almost 13 percent do. Emily Jan/NPR hide caption

itoggle caption Emily Jan/NPR

Cushing, Okla., is a major oil storage site. Amid record oil production, some analysts worry the U.S. will run out of places to put it all. Daniel Acker/Bloomberg via Getty Images hide caption

itoggle caption Daniel Acker/Bloomberg via Getty Images

A riot late last month forced officials to close the Willacy County Correcitonal Center in Wallcy County, Texas. John Burnett/NPR hide caption

itoggle caption John Burnett/NPR

The logo of Swiss bank UBS is seen at the company's headquarters in Zurich. U.S. officials are investigating whether UBS and Barclays manipulated currency rates at a time when they were already operating under a deferred prosecution agreement for manipulating interest rates. Arnd Wiegmann/Reuters/Landov hide caption

itoggle caption Arnd Wiegmann/Reuters/Landov