An Incan citade in the Andes mountains in Peru. (Above the Urubamba River Valley) The original use of it is not known, but we do know it was built in the 15th century.
Wich of what you've got not answer choices
After fighting the war in Korea, the US had learned that communism would spread. In order to keep with their policy of containment, they had to rush in and stop Viet Cong from spreading communism (much like the domino theory that the US had). Had Viet Cong not wanted to bring about communism, there would be no need for invasion, and the domino theory would have yet to be proven.
:)
short answer: pearl harbor.
