Run-up for the Cuban missile crisis

Contrary to the impression that one may receive from the popular historical accounts, the Cuban missile crisis did not come out of nowhere, but had been preceeded by extensive nuclear preparations. It is hardly conceivable that during the previous year either Kennedy or Khrushchev had any doubts that they were gearing up for the total war:

"What followed was a veritable nuclear-testing frenzy. More than 250 tests were conducted in the 16 months following the aborted attempt to put the nuclear genie back in its bottle – more explosions than in the 16 preceding years. One test explosion set the infamous record for the largest-ever manmade explosion: the Soviet Tsar bomb, detonated on October 30, 1961, was the equivalent of 4,000 Hiroshima bombs. It is no coincidence that a year later, in October 1962, the world found itself on the brink of nuclear war during the Cuban missile crisis." [Emphasis mine]