<p>Cuba had been a thorn in the side of the US ever since Fidel Castro took power on 2 January 1959. The United States broke diplomatic relations with the island, and in April 1961, encouraged, supplied and then failed to support an invasion by exiles.
</p>
<p>The Bay of Pigs fiasco loosed an avalanche of arms from Cuba's new protector, the Soviet Union. Everything from pistols to artillery, MiG-15s to MiG-21s, motor torpedo boats and coastal patrol ships had been delivered. Following a July 1962 visit to Moscow by Raul Castro, then Defense Minister, there was a noticeable upturn in the volume of shipping reaching Cuba. The harbors of Havana and Mariel were crowded. Strangely, the Russians kept all Cubans away from the docks during the off-loading, and handled the heavy work with their own deckhands and stevedores.
</p>
<p>Some Cuban refugees reported seeing things that looked like rockets; others, with some technical skills, were able to make sketches in sufficient detail to confirm what had been only a suspicion. The Russians had brought anti-aircraft missiles to Cuba.
</p>
<p>Ever since the break in diplomatic relations, Cuba had been the subject for an occasional reconnaissance flight by one of the CIA's Lockheed U-2 aircraft. The Cubans were able to identify, but not intercept, the gray planes. They knew that a U-2 piloted by Francis Gary Powers had been shot down by a Russian missile on 1 May 1960, and they probably pointed out to the Russian advisers that Cuba ought to have the same opportunity, in order to prevent further incursions of Cuban airspace and reconnaissance of the island.
</p>
<p>A U-2 mission was routed over the suspected areas of missile deployment on 29 August 1962, and it brought back the first photographic evidence of the missile sites. At least two were positively identified, and six others looked suspiciously like anti-aircraft missile batteries. In a third section of Cuba, the photos showed a short-range coastal defense missile battery, the type used against an invading force or a pre-invasion naval action.
</p>
<p>The U-2 overflights were scheduled for 5, 17, 26 and 29 September, and 5 and 7 October. Each one brought back more information. Three new SAM sites and three more cruise missile sites were spotted. What the U-2s could not photograph was the arrival of offensive ballistic missiles. They reached Cuban ports about 8 September, and were off-loaded and moved at night for concealment.
