By the summer of 1962, the end of the world was 90 miles away.
The Soviet Union was building something in Cuba, the crescent-shaped island an overnight boat ride from Miami, and Bob Boyd and a team of CIA and military analysts had secretly watched as a submarine base and defensive surface-to-air missile systems rose on a farm outside Havana.
They watched and waited all summer, poring over aerial surveillance photos.
"(CIA Director John McCone) and President (John F.) Kennedy were worried the Soviets might deploy offensive missile systems in Cuba," said Boyd, now 86 and living on Hilton Head Island. "The president wanted to know immediately if there was any indication of that."
A U-2 flight on Oct. 14 confirmed Kennedy's worst fears, terrified a nation and brought two global superpowers to the edge of nuclear annihilation.
Fifty years later, Boyd remembers the day those photographs showed up at his office near 5th and K streets in Washington.
"It was very upsetting because of the potential of having a nuclear system deployed in Cuba that could send missiles over our country," Boyd said last week on the 50th anniversary of the crisis. "The feeling was that we ought to get out of Washington. It was within range."
A LONG-RANGE THREAT
The U-2, a reconnaissance plane with a single jet engine, took off from a base near Roswell, N.M., bound for Cuba, five hours away by air.
Its mission was simple: capture images of the ongoing Soviet buildup.
When the plane, whose existence and missions were highly classified, touched down hours later in Florida, the film was flown to Washington, where it was developed by Navy experts and brought to the National Photographic Interpretation Center, where Boyd and his team waited.
What they saw threatened to turn the Cold War red hot.
"You could clearly see these canvas-colored objects that measured about 70 feet in length," Boyd said. "We knew that their SANDAL missiles were about 74 feet long, because the Soviets would pull (them) through the May Day parades and we took pictures of them. It was clear to us that we were looking at medium-range ballistic missiles and missile sites."
Still, Boyd and his team took their time to be sure. They scrutinized the photographs for hours, knowing that misidentifying the weapons systems could have deadly consequences.
But Boyd, who joined the CIA in 1956, was by 1962 an old hand.
He knew exactly what he was looking at.
COULD IT BE AVOIDED?
Boyd and his team shared what they'd found with officials at the photographic center and the CIA.
On Oct. 16, Kennedy got a look at the photographs.
The U-2 continued to fly missions over Cuba. It discovered additional sites and more missiles, all of them capable of reaching nearly every major U.S. city.
Meanwhile, Kennedy met secretly with his advisers to discuss a response. By Oct. 22, it was settled. Only Boyd and a few others knew what the president would say when he appeared on television from the Oval Office.
What Kennedy told the nation that day was sobering. The Russians had installed missiles that could devastate America. He demanded the weapons be dismantled and removed.
He also announced a naval blockade of the island to prevent more military supplies from entering.
Kennedy concluded with a grave warning: "It shall be the policy of this nation to regard any nuclear missile launched from Cuba against any nation in the Western Hemisphere as an attack by the Soviet Union on the United States, requiring a full retaliatory response upon the Soviet Union."
Boyd, like nearly every other American of the era, watched the address on television.
"The military was pressing for an invasion of Cuba, but luckily Kennedy took the right course of action with the blockade," Boyd said.
"In doing so, he staved off what could have been a pretty serious exchange, which I don't think anyone wanted. I don't even think the Soviets wanted that at that time."
But the question was, could it be avoided?
A SAFER WORLD
The standoff that gripped the world was resolved on Oct. 27 when Kennedy and Soviet leader Nikita Khrushchev agreed to a deal in which the Soviets would dismantle the weapons sites in exchange for a pledge from the United States not to invade Cuba.
In a separate deal that remained secret for more than 25 years, Kennedy also agreed to remove U.S. nuclear missiles from Turkey, according to records from the President John F. Kennedy Presidential Library and Museum in Boston.
Both sides managed to save face without pushing the button.
The eventual willingness of both sides to deal indicated how close they'd come to nuclear holocaust, said David Snyder, a history professor at the University of South Carolina.
"Once that initial perception of American 'victory' in the Cuban Missile Crisis subsided, cooler heads began to understand just how close to nuclear disaster the world had come," Snyder said.
No one, American or Soviet, wanted to come that close again.
"This would lead to mounting efforts at rapprochement between the (two countries)," Snyder said, "as each side sought ways to defuse the nuclear tensions in the world."
Boyd was now part of that effort.
"We had to identify and make sure the missiles were leaving," he said. "From more U-2 photographs, we were able to see the missiles on the boats leaving and in the ports ... and could see the Soviets bulldozing the launch sites so that they were no longer usable."
And the world, at least for that moment, was safe.
A GRATEFUL PRESIDENT, A SECRET THANKS
As the crisis was winding down, Art Lundahl, the center's director and Boyd's boss, received a letter from Kennedy in early November.
The letter, which Boyd has a copy of, thanked Lundahl and his staff for their work and expressed regret that Kennedy could not acknowledge them publicly.
Secrecy and anonymity, however, were standard operating procedure.
"Our work was highly classified," Boyd said. "We were still flying U-2 missions over the USSR, and they didn't want the Soviets to know. They wanted to keep secret what we were doing, and we were fine with that.
"We were just doing our jobs."
In early 1963, the CIA presented Boyd with the Intelligence Medal of Merit, one of its highest honors, for his role in defusing the crisis.
Fifty years later, Boyd sat in the living room of his Hilton Head Plantation home and looked at the medal and a photograph of a much younger version of himself accepting it from McCone.
Boyd smiled at the memory.
"It's hard to believe, really," he said. "We were all working so hard. We were so eager to get into work every day to look at the photography because you were making new discoveries all the time. You would discover something and the next day that information would be in the White House."
ONCE A SPY, ALWAYS A SPY
For nearly 20 more years, Boyd worked in aerial reconnaissance, studying U-2 photographs and, later, satellite images of the Soviet Union and its weapons systems.
He ascended the ranks of the CIA before retiring in 1980. He has lived on Hilton Head for more than 30 years.
Though long since retired, Boyd said he now uses a common Internet tool to keep his old spy skills sharp -- Google Earth.
"I go on there, look at the former USSR, and I can still see some of my old sites," he said.
He pauses for a moment and grins.
"There's a few new ones on there, too. Yeah, I guess I've still got the eye."
Follow reporter Patrick Donohue at twitter.com/ProtectServeBft