NATO Secretary General Lord George Robertson (center) is given a briefing at the Pentagon crash site by Michael Sullivan (left), deputy program manager of the Pentagon Renovation Office, on Oct. 10, 2001. The damage was caused when a hijacked American Airlines flight slammed into the building on Sept. 11th. The terrorist attack caused extensive damage to the west face of the building and followed similar attacks on the twin towers of the World Trade Center in New York City.