September 11, 1941
Appearance
September 11, 1941 was the ground breaking date for construction of The Pentagon. On September 11, 2001, exactly 60 years after the building's groundbreaking, hijacked American Airlines Flight 77 was crashed into the western side of the Pentagon, killing 189 people, including five hijackers, 59 others aboard the plane, and 125 working in the building.