$Crises of the Cold War

US Leadership

1955 - 20 January 1961
20 January 1961 - 22 November 1963
22 November 1963 - 20 January 1969
20 January 1969 - 31 December 1970

USSR Leadership

27 March 1955 - 14 October 1964
14 October 1964 - 31 December 1970

UK Leadership

1955 - 1957
1957 - 1963
1964 - 31 December 1970

Events

June 1956 - November 1956
1960
April 1961 - 28 October 1962
13 August 1961
1968 - 20 August 1968