NSA tracking cellphone locations worldwide, Snowden documents show

According to an article in the Washington Post,  documents revealed by Edward Snowden show that the NSA "is gathering nearly 5 billion records a day on the whereabouts of cellphones around the world, according to top-secret documents and interviews with U.S. intelligence officials, enabling the agency to track the movements of individuals — and map their relationships — in ways that would have been previously unimaginable."