The National Security Agency headquarters at Fort Meade, Md. Saul Loeb/Getty Images hide caption

toggle caption Saul Loeb/Getty Images

A checkpoint leading to the closed U.S. Embassy compound in the Yemeni capital, Sanaa, on Saturday. Mohammed Huwais /AFP/Getty Images hide caption

toggle caption Mohammed Huwais /AFP/Getty Images

Edward Snowden, seen during a video interview with The Guardian. Glenn Greenwald/Laura Poitras/EPA/Landov hide caption

toggle caption Glenn Greenwald/Laura Poitras/EPA/Landov

Edward Snowden, seen during a video interview with The Guardian. Glenn Greenwald/Laura Poitras /EPA /LANDOV hide caption

toggle caption Glenn Greenwald/Laura Poitras /EPA /LANDOV