There was a summit meeting between US President Dwight Eisenhower and Soviet Premier Nikita Khrushchev in the US in 1959. The two leaders agreed to meet again in Paris the following year.
The American military wanted to spy on the Soviets to discover evidence of this missile building. President Eisenhower agreed to the spy missions because he believed it would show that there was no missile gap between the USSR and USA.
Just thirteen days before the Paris Summit, on 1 May 1960, an American U2 spy plane, piloted by Gary Powers, was shot down over the USSR. The USA claimed that the U2 was a weather monitoring plane that had lost its way. However, the film that the Soviets retrieved from the plane clearly indicated that Powers had been on a spying mission.
When President Eisenhower arrived in Paris for the summit meeting, Khrushchev demanded he apologise for the mission, and when Eisenhower refused Khrushchev walked out.
The Paris Summit ended in failure: