Final answer:
On September 11, 2001, besides the World Trade Center in New York City, the Pentagon, the headquarters of the United States Department of Defense in Washington, DC, was also targeted and hit by a hijacked plane.
Step-by-step explanation:
On September 11, 2001, the World Trade Center in New York City was not the only building targeted by hijacked planes.
Another target was the Pentagon, which is the headquarters of the United States Department of Defense located in Washington, DC.
A third plane, United Airlines Flight 93, was also hijacked and heading towards Washington, DC, but it crashed in a field in Shanksville, Pennsylvania, after passengers tried to regain control of the plane.