Fields of carrots are watered March 29, 2015, in Kern County, Calif. Subsidized water flowing in federal and state canals down from the wet north to the arid south helped turn the dry, flat plain of the San Joaquin Valley into one of the world's most important food-growing regions. Frederic J. Brown/AFP/Getty Images hide caption

Tents are pitched illegally on a sidewalk in Seattle in January. The number of people sleeping outside in the city shot up by 20 percent in just the past year. David Ryder/Reuters/Landov hide caption

Apps like Venmo promise easy, carefree money transfers between friends. Noah Nelson/Youth Radio hide caption

NYU medical student Sara Stream (left) examines dancer Jazlyn Caing, who visited the clinic for low-grade orthopedic and respiratory problems. Fred Mogul/WNYC hide caption

Bill Nighy is starring a revival of David Hare's 1995 drama Skylight. "I adore it. It's probably my favorite play," he says. John Haynes/Philip Rinaldi Publicity hide caption

The number of women buying, selling and sharing breast milk is growing rapidly. But it can be a risky purchase, scientists say, because a mom can't tell by looking at the milk whether it's safe and nutritious for her baby. iStockphoto hide caption

Depending on the amount taken in subsidies, or changes in reported income and family status, some Obamacare policyholders this year will get a bigger refund than expected and others will owe more in taxes. Carolyn Kaster/AP hide caption

A Colombian soldier searches for land mines laid by rebel fighters. RAUL ARBOLEDA/AFP/Getty Images hide caption

Billie Holiday has become a mythic presence in absentia. William Gottlieb/Getty Images hide caption