"NBC Nightly News" anchor and managing editor Brian Williams traveled to Moscow this week for an exclusive, wide-ranging interview with Edward Snowden. The former NSA contractor's first-ever American television interview will air in an hour-long NBC News primetime special on Wednesday, May 28 at 10 p.m. Eastern/9 p.m. Central.

Williams' in-person conversation with Snowden was conducted over the course of several hours and was shrouded in secrecy due to Snowden's life in exile since leaking classified documents about U.S. surveillance programs a year ago. Williams also jointly interviewed Snowden and journalist Glenn Greenwald, who has reported stories based on the documents in media outlets around the world, about how they came to work together and the global debate sparked by their revelations.

Snowden, now 30, is a former systems administrator for the CIA who later went to work for the private intelligence contractor Dell inside a National Security Agency outpost in Japan. In early 2013, he went to work for Booz Allen Hamilton inside the NSA center in Hawaii.

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While working for the contractors, Snowden downloaded secret documents related to U.S. intelligence activities and partnerships with foreign allies, including some that revealed the extent of data collection from U.S. telephone records and Internet activity.

On May 20, 2013, Snowden went to Hong Kong to meet with Greenwald and with filmmaker Laura Poitras. The first articles about his documents appeared in the Guardian and The Washington Post in early June, as did a taped interview with Snowden.

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The U.S. government charged Snowden with espionage and revoked his passport. Snowden flew to Moscow on June 23, but was unable to continue en route to Latin America because he no longer had a passport.

After living in the airport transit area for more than a month, and applying for asylum in more than 21 countries, he was granted temporary asylum in Russia, where he has been living ever since.

U.S. officials have asserted that Snowden may have taken as many as 1.7 million documents. Among the revelations from documents in the Snowden trove are the NSA’s bulk collection of phone and internet metadata from U.S. users, spying on the personal communications of foreign leaders, including U.S. allies, and the NSA’s ability to tap undersea fiber optic cables and siphon off data.

President Barack Obama responded by appointing a review panel that criticized the NSA's domestic data collection, and in March he recommended ending bulk domestic metadata collection. This week, the House passed a bill to end the NSA’s bulk domestic metadata collection.