Militiamen trained in the Escambray mountains while superpowers tested each other’s resolve. The background in this composite image is from a U-2 photo of Cuba.

© Hulton-Deutsch Collection / Corbis

On June 6, 1961, less than two months after the failed U.S.-backed invasion of Cuba at the Bay of Pigs, enormous wooden crates arrived at San Antonio de los Baños air base on the western part of the island, along with more than 100 Soviet troops. Inside the crates were MiG-15s and -19s, the first weapons in a buildup in Cuba that included Soviet fighters, bombers, radar, anti-aircraft batteries, and eventually the nuclear missiles that would ignite the 13-day standoff between the United States and the Soviet Union in October 1962. Today, 50 years after the Cuban Missile Crisis, Cubans recall how their government prepared them for what it insisted was the conflict’s inevitable end: all-out war with the United States.

A year after the MiGs arrived, Cuba’s armed forces chief, Raul Castro, younger brother of Cuban leader Fidel Castro, signed a secret agreement in Moscow allowing the Soviets to introduce offensive nuclear weapons to the island, just 90 miles from the Florida Keys. Not long afterward, truckloads of Soviet military equipment began flooding into Cuba.

Miami resident Roberto Canas was a 13-year-old schoolboy living at the time near the small town of Moron. (He asked that his real name not be used since he travels regularly to Cuba to visit relatives.) Canas remembers playing in his front yard and seeing the convoys roll past. “We would see big trucks loaded down with all kinds of heavy equipment covered by large tarps traveling the roads around Moron,” he recalls. “We had no idea what was under those tarps. It was only because the trucks were under military guard that we knew that something important was being carried on them.”

For days, the mysterious trucks rumbled through the Cuban streets, highways, and countryside. Enormous 18-wheelers moved in convoys that stretched for hundreds of yards, cutting off traffic. Rumbling through rural villages and narrow paved roads, the convoys would sometimes pause while power lines and mailboxes along the route were removed to make room for their passage. Occasionally, a home, encroaching on the narrow road, was torn down. As the trucks passed through the various towns, they left a trail of downed telephone poles and crushed huts.

I had left Cuba, as a seven-year-old, two years before the missiles came, but I have heard many stories about what it was like on the island for the people who stayed. “Few, if any, Cubans really put two and two together,” Rafael del Pino writes me in an e-mail. Del Pino, a hero of the April 1961 Bay of Pigs invasion, had flown a Lockheed T-33 jet, shooting down two Douglas B-26 Invaders and sinking several CIA ships. “At that time, most Cubans listened to the government line that the U.S. wanted to invade the island. And after the Bay of Pigs, that was [believable]. The [propaganda] coming from our own government made us think we were going to be invaded by U.S. forces and the Soviet Union was defending us.”

Del Pino’s performance in 1961 set him on a course to become Castro’s chief air force adviser and, as such, a key eyewitness to the missile crisis. Today, at 74, the retired general is living in Europe under the U.S. Federal Witness Protection Program. One of the top-ranking defectors from the Cuban government, he fled Cuba in May 1987.

Del Pino recalls dozens of MiG-21F.13 fighters arriving at Santa Clara air base in central Cuba in August 1962, to be assembled by Soviet engineers. “When 44 aircraft were ready to fly, we knew something of great significance was up,” del Pino writes in Inside Castro’s Bunker, a memoir of his life in Cuba, published last July. “There were not enough pilots in Cuba, even including the ones with flight training in the Soviet Union, to complete the MiG-15 and MiG-19 squadrons we now had.” On September 15, about 50 Soviet pilots arrived at the base.

“Any lingering doubt as to what was about to happen disappeared in early Octobe