Which buildings did Osama bin Laden's organization attack on September 11, 2001?
Washington Monument and the White House
CIA headquarters and the Supreme Court
Capitol building and the Internal Revenue Service
World Trade Center and the Pentagon

The world trade center (Twin towers) and the Pentagon

Explanation:

Since these two (or should I say three) buildings were important to the U.S because they had Trading for the U.S and the Pentagon was more like a security base. After that they were going to hit the White house, but the heroic passengers of the hijacked airplane attacked the hijackers so they wouldn't hit the white house and kill Obama. (R.I.P. heroic people)