Oct. 23, 2012 --

The world came within days, perhaps hours, of ending 50 years ago this week when the United States and the former Soviet Union stood at the brink of nuclear war. The dispute was over the placement of Russian missiles in Cuba. For 13 days, President John F. Kennedy and Soviet Premier Nikita Khrushchev stood eye-to-eye; from Oct. 16, 1962, when the missiles were discovered by an American surveillance aircraft, until Oct. 28, 1962, when Kruschchev publicly announced he would pull them out. The crisis grew to engulf not only the two countries, but much of the world standing on the sidelines. Here are some images of that time, beginning with this low-altitude view of the Russian missile installation at San Cristobal, Cuba.

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This image taken from a high-altitude U-2 spy plane showed the first direct evidence of emplacements. The Soviets installed 36 to 42 medium SS-4 medium-range ballistic missiles. Six were decoys. A total of 96 warheads arrived on the island as well. The missiles had a range of 1,266 miles, capable of knocking out New Orleans, Miami, and Washington, D.C. Each missile's warhead had an explosive capacity of about one megaton, more than 60 times the destructive power of the atomic bomb dropped on Hiroshima, which was 16 kilotons, according to Harvard University's Belfer Center for Science and International Affairs. There were also 92 short range missiles, 42 unassembled IL-28 bombers and 40,000 Soviet troops on Cuban soil at the time of the crisis.

The backdrop to the Soviet missiles was the worsening Cold War between the U.S. and the U.S.S.R., and the warming relationship between the Soviet Union and Cuba. Beginning in 1960, when Khrushchev met Cuban leader Fidel Castro at the United Nations, the two nations forged strong trade and military ties. In 1961, Cuba formally joined the Soviet bloc, while exiles trained by the CIA launched the bungled Bay of Pigs invasion from south Florida. "For us Castro, he was a hero," said Sergei Krushchev, son of the former Soviet leader and now a Slavic studies professor at Brown University. "It became like David and Goliath. He challenged the United States, the greatest country of the world. It was the same for my father."

Kennedy is told by national security officials on the morning of Oct. 16 that nuclear missile bases are in Cuba. He convenes a panel of his closest military and civilian advisers that meet privately for a week to discuss their options. Kennedy’s EX-COMM group discuss the possibility of bombing the bases, but realize an amphibious invasion will have to follow to ensure their destruction. This photo shows a Russian ship carrying bomber fuselages to Cuba. Tensions were high, and the first instinct was to attack, according to Graham Allison, director of Harvard’s Belfer Center. "Later, Kennedy in his memoirs, says the chances (of an attack) were between one-in-three and even," Allison said. "There’s nothing in record that that was an exaggeration."

On the night of Oct. 22, President Kennedy publicly announces the discovery of the missiles and a naval blockade of Cuba to prevent "offensive weapons" during a nationwide TV address. The blockade includes dozens of U.S. warships, submarines and aircraft. It prevents longer-range missiles from reaching Cuba that would have been capable of reaching much of the U.S. mainland. Meanwhile, backchannel negotiations begin between Soviet ambassador Anatoly Dobrynin and Attorney General Robert F. Kennedy. On Oct. 24, several Soviet ships reverse course before reaching the blockade; others pass through. Sergei Khrushchev said the blockade was a compromise by Kennedy. "The blockade was diplomatic language, which was an invitation to negotiation," Krushchev told Discovery News. "It said: 'You sending these ships and showing they are not carrying any weapons. Yes, I agree they can go through.'"

The U.S. public fears nuclear war. On Oct. 25, U.N. Ambassador Adlai Stevenson convenes a meeting of the Security Council and presents photographs of the Soviet missile sites. The next day, Krushchev sends a private letter to the White House stating he will remove the missiles if the U.S. agrees not to invade Cuba now or in the future. On the Oct. 27, a second letter arrives, stating that Krushchev also wants the U.S. to remove nuclear missiles in Turkey. On Oct. 28, the Soviet premier agrees publicly to withdraw the bases and missiles in exchange for the no-invasion pledge. A secret deal is also reached to remove the U.S. missiles. By Nov. 20, the Cuban missiles are gone, the fields are plowed over, and the naval blockade is lifted. Sergei Kruschev, who was a 27-year-old Soviet missile engineer at the time, said there's one big lesson to be learned. "You have to negotiate with your enemy, not with your friends," he said. "Now we will say we will impose unconditional surrender with Iran. Of course they won't accept this. Sooner or later, like in any bargaining, you will come to a resolution of this crisis too."

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