The correct answer to this open question is the following.
The type of evidence that Winston Churchill's "Iron Curtain speech" is trying to convey was the kind of control and dominance the Soviet Union is exerting in some European countries, establishing what he called "an iron curtain that has descended across the continent."
He delivered this speech on March 5, 1946, in a College in Fulton, Missouri, before US President Harry S. Truman. Both men expressed their concerns about the international scenario and USSR activities under the leadership of Joseph Stalin that wanted to spread Communism in different nations.