The Discovery Communications headquarters building is seen in Silver Spring, Maryland in this December 3, 2009 file photo. One hostage has been taken by a man with a handgun at the Discovery Channel headquarters building in suburban Washington, Montgomery County police told ABC television on September 1, 2010. The hostages were safe. The gunman, who apparently objected to the TV channel's environmental coverage, died, NBC television network said, quoting law enforcement sources. [China Daily/Agencies]