While the U-2 spy plane is largely credited for identifying the presence of Soviet missiles in Cuba in the early 1960s, setting off a Cold War escalation with nearly-apololyptic results, new research has pieced together how CIA-trained Cubans ran a highly-successful intelligence network that drove the discovery of the missiles. Two contextual issues at the time had led to an American intelligence gap: the strong assumption in the intelligence community that Russia would not risk sending missiles to Cuba and fears of repeat U-2 disaster. The U.S. had been running bi-weekly U-2 flights over Cuba, but the installment of SA-2 surface-to-air missiles that had successfully shot down the American U-2 plane over the USSR in 1960 caused the plan to diverge and the US discontinued its reconnaissance missions over Western Cuba completely. With the successful planting of two CIA-trained Cuban agents several months earlier, however, valuable intel began streaming from the growing network into the CIA’s operations HQ in Miami, the agency’s largest office outside Langley in 1962. This intel alerted the U.S. to ongoing top-secret Soviet operations in the country that was most likely covering missile movements. With this intel, a U-2 was sent over Western Cuba and confirmed the presence of intermediate-range Soviet missiles. Following the discovery, the network’s leader urged the U.S. to support a guerrilla war against the Cuban government, but the U.S. refused. By early 1964, the network was penetrated and many of its members executed.
Source: How a CIA agent trained agents who found Soviet missiles in Cuba