December 21 in history, these intelligence were sent to the US president

情报历史上的12月21日，这些情报被递交给时任美国总统

Intelligence History on 1961 December 21
Intelligence History on 1962 December 21
Intelligence History on 1963 December 21
Intelligence History on 1964 December 21
Intelligence History on 1965 December 21
Intelligence History on 1966 December 21
Intelligence History on 1967 December 21
Intelligence History on 1968 December 21
Intelligence History on 1970 December 21
Intelligence History on 1971 December 21
Intelligence History on 1972 December 21
Intelligence History on 1973 December 21
Intelligence History on 1974 December 21
Intelligence History on 1976 December 21