Cuban missile crisis

The Cuban Missile Crisis began October 14, 1962, when an American spy plane flew over Cuba photographed the construction of several missile deployment sites. Kennedy did not begin consulting with world leaders until a few days into the crisis, and when Diefenbaker was informed about the situation he doubted the intelligence that he was provided - asking for more photographs of the missile sites in Cuba. Diefenbaker refused to put Canadian troops on alert,  and deliberated for days over raising the military awareness level to DEFCON 3. 

Eventually Diefenbaker did agree to put Canadian troops on alert, as all other NATO members supported a proposed blockade and agreed to aid the United States if an attack occurred. The Cuban Missile Crisis was the most heated moment of the Cold War.  As these two hegemonic superpowers struggled for ideological dominance, the world lived in fear of nuclear annihilation.