In May 1960, Francis Gary Powers was flying a spy plane when it was shot down over the Ural Mountains. He returned to the United States in 1962 as part of a trade for a Soviet spy. (UPI)

On the opposite end of the steel-trussed Glienecke Bridge was Col. Rudolph Abel, the highest-ranking Russian intelligence officer to be caught spying in the United States.

At 8:52 a.m., the two men began walking forward. They passed each other and made eye contact. Neither said a word.

It was a dramatic — and surprisingly peaceful — end to a political crisis at a time of extreme tensions between the United States and the Soviet Union.

For his bravery during the crash and his imprisonment, the Air Force recently decided to honor Powers with the Silver Star, the military’s third-highest award for valor. A Defense Department ceremony for Powers, who died 35 years ago, will be held later this year.

“He’s deserving of this medal,” the airman’s son, Francis Gary Powers Jr., said in an interview.

On May 1, 1960, Powers’s plane was brought down by a Russian missile over the industrial city of Sverdlovsk, about 1,100 miles east of Moscow. After escaping from the cockpit as the aircraft twirled toward the earth, Powers parachuted to safety but was arrested by Russian authorities. He was convicted of spying and sentenced to 10 years in prison.

The incident caused a rift between the United States and the Soviet Union. Diplomatic relations reached an all-time low. An international summit in Paris collapsed after Soviet Premier Nikita Khruschev demanded that the White House apologize for spying.

Through a series of negotiations, a prisoner exchange was engineered by American lawyer James B. Donovan. Abel had been arrested in New York in 1957 for spying while posing as an artist in Brooklyn Heights. President John F. Kennedy commuted Abel’s 30-year sentence in return for Powers’s freedom. The resulting exchange was the start of a tradition in spy swaps that still continues today.

“The spy game is alive and well,” Powers Jr. said. “All countries spy. The end result is that an agent gets caught.”

When Powers was released early, on Feb. 10, 1962, White House officials roused Washington newspaper correspondents from their beds for a 3 a.m. news conference. His freedom made the front pages of The Washington Post and New York Times.

Powers’s reception by the American public was not particularly warm. Speculation circulated that Powers had been turned by the Soviets and was a double agent. Others alleged that he had disobeyed CIA orders by admitting to the Russians his role as a U.S. spy. Not long after returning to the United States, Powers resigned from the CIA and became a private pilot. For years, his son said, Powers had nightmares about his imprisonment in Russia.

He died in 1977 when a helicopter he was piloting crashed in California. He is buried at Arlington National Cemetery, on a hill not far from the Tomb of the Unknowns.

“We’re just delighted to know he will be awarded” the Silver Star, Powers Jr. said. “It’s never too late to have the government set the record straight.”

Powers Jr. often asked his father about the crash and his time in Russian custody. One question his father never answered was how high he had been flying that day in 1960.

Powers told his son that the information was highly classified, but that one thing was certain.

“Gary,” his father told him, “I wasn’t flying high enough.”

Powers was not the only American prisoner released half a century ago today.

Frederic L. Pryor was a 27-year-old Yale graduate student studying in East Germany when he was arrested in August 1961 by the Stasi and accused of passing on sensitive trade documents to the Americans.

He spent five months in prison before he was released in a deal negotiated by Donovan.

Contacted by The Post, Pryor, now 78 and a professor emeritus of economics at Swarthmore College, said he didn’t remember much about his experiences in East Germany and considered his part of the story on the day of the release “totally uninteresting.”

“I’ve really done my best to try to forget everything,” he said.