Dwight D Eisenhower, US president, 1953-1961
U-2s
Josef Stalin, Soviet dictator, 1924-1953
Nikita Khrushchev, General secretary, 1953-1964
The USA developed the atomic bomb in 1945, and they used it on Hiroshima and Nagasaki. In 1952, they created the hydrogen bomb after the Soviet Union copied the atomic bomb. Finally in 1957, they tested the inter-continental ballistic missile (ICBM).
The Soviet Union was worried about the atomic bomb. This gave the US an edge in the Potsdam conference. Stalin ordered that his scientist create a version of the bomb, and by 1949, they had one. They then managed to copy the hydrogen bomb in 1953, but they were then the first to launch the ICBM in 1957. This put them ahead in the arms race.
The missiles would fly over the artic, as this was a shorter distance than over the Atlantic and Europe. It would also not violate any neutral country's airspace.
The results of a nuclear war would have been devastating. By the 1980s, the US and the Soviet Union had enough missiles to blow the world up several times over. In the Cuban missile crisis, had the US, and the USSR gone to war, in the first wave of missiles alone, 100 million people would have died from the US alone, and another 100 million from the USSR.
Both the US, and the USSR had missiles based in other nations, to put them as close to the other as possible. For example, the US put missiles in Turkey, so in response, the USSR placed missiles in Cuba, resulting in the Cuban missile crisis.
Later, treaties were signed. These regulated missiles, like one banned putting missiles into the earth's orbit, or into space. These were a crucial part of Détente.
Richard Nixon, US president, 1969-1974
Leonid Brezhnev, General secretary, 1964-1982