The problem has had a wide impact, keeping farmworkers, Ultimate Fighting Championship athletes and foreign students from entering the U.S. The agency has 100 experts working on a fix.
When it comes to test scores, students at Michigan's Brimley Elementary School are well above the state average. About half its students are Native Americans, many are from low-income families.
Several dozen recreation centers offer aftercare and summer camp for children in the city's poorest neighborhoods. But they also give kids the family stability and structure that so many of them lack.
Behind the walls at Emerson High School in Oklahoma City, construction workers found old chalkboards with drawings and class lessons, written almost a century ago and in remarkable condition.
In just 18 months, China has created more than 2,000 acres of new land where before there were just waves and reef, according to the U.S., which sees the work as a threat to regional stability.
For many Americans, an NPR poll suggests, walking is their most consistent exercise. But how much can a moderately paced walk really help your health?
When the Pentagon revealed it secretly exposed enlisted men to mustard gas during WWII, VA officials promised disability benefits. But an NPR investigation finds that most were never contacted.
Driven by new regulations and fracking, more coal power plants are retiring for cheaper, cleaner-burning natural gas. But scientists have yet to work out the fossil fuel's imperfect climate footprint.
When Sen. Marco Rubio's parents came to the U.S., they put down roots in West Miami, a nearly all-Cuban neighborhood. That's where the senator and his family still live.
For the first time ever, the U.S. Army Corps of Engineers has closed part of a navigable waterway to stem the migration of an invasive species.