Eavesdropping on the world

From its headquarters outside Washington, D.C., the supersecret National Security Agency eavesdrops on literally billions of communications worldwide. But for some, the awesome power of the NSA is a source of concern. CNN National Security Correspondent David Ensor takes a behind-the-scenes look at the NSA in a special series airing the week of March 19-23.

Monday: The codebreakers
Tuesday: Spying on you?
Wednesday: The codemakers
Thursday: The listener
Friday: The traitor problem