HUDSON, Mass. (Tribune News Service) — All these years later the prison walls talk again — through coded knocks, projected images and narration.

The American Heritage Museum's "Hanoi Hilton" exhibit opened Sunday with 20 former American prisoners of war on hand and two cells reassembled from materials salvaged decades ago in Vietnam at the infamous Hòa Lò prison.

Part of the Hanoi prison, formerly a French colonial house of detention, was demolished for development in the 1990s. Artifacts and building materials were collected and stored.

The Hudson exhibit marks 50 years since Feb. 12, 1973, when the first POWs were released from Hòa Lò.

U.S. Navy pilot Capt. Leo Hyatt, 88, from Salem, N.H., was a prisoner at Hòa Lò for more than five years, released March 14, 1973.

U.S. Navy pilot Capt. James Mulligan, 96, from Lawrence, Mass., spent part of his 7-year imprisonment in the infamous Hanoi cells after his plane was downed March 20, 1966.

Hyatt now resides at a VA hospital and Mulligan died Jan. 18.

Their stories, and those of their families, are told through the museum's exhibit.

"All of them were tortured through starvation and physical torture," said Hunter Chaney, museum communications director.

Among the POWs at the opening were U.S. Navy Capt. John Michael McGrath, U.S. Air Force Col. Thomas Kirk, and U.S. Navy Lt. Cmdr. Timothy Sullivan of Acton, Mass.

In videos projected on the cells' walls, POWs speak of how they got there, the isolation, torture and starvation they endured, and how communication helped them survive.

"The story I want everyone to take away, is the survival story, and communication was essential for them to survive," said Rob Collings, CEO of the Collings Foundation, which houses the museum.

Code a key to survival

The POWs, isolated in cells separated by thick brick walls, would reach out to any occupant in an adjoining cell with call and response knocking, dubbed "shave and a haircut." This was to determine if anyone was there and if they were American.

One person taps five notes: "duun, dun-dun, duun duun."

If from the other side of the wall, following a silence, came two response knocks "duun duun," the prisoners knew those replying were Americans.

As Kirk and McGrath explain, the "shave and haircut" rhythm was part of every American's lexicon, so widespread was it in movies and music.

The sound all Hanoi Hilton POWs dreaded was that of jangling keys approaching in the hallways, a sign that a guard was coming to take one of them out to be tortured.

It was also between these thick walls that a tap code based on a grid and the alphabet was established among the POWs. It was crucial to morale, to withstanding the brain-racing stress, for some, during years of isolation.

"One of the cruelest punishments for anyone is when your mind is whirling 24 hours a day — and it doesn't stop," said Kirk.

Having that tapping back and forth, where they could start to talk, meant everything to them.

Later, as the end of the war approached, POWs were removed from isolation and put into cells together where they were in a constant state of learning, of teaching languages and math and auto repair to each other.

One POW, who entered speaking one language, left being able to speak four.

Families stories told, too

Between February and March of 1973, North Vietnam released 591 American servicemen, most of them officers and airmen.

Operation Homecoming was a much better experience for the POWs than the often scornful response college students and others gave soldiers and Marines who had served during the war. The POWs received warm welcomes and intensive psychological and medical care.

Yet, for many of the married POWs, the long separations from their wives were too great to overcome and the couples divorced.

Leo Hyatt, who grew up on a Salem Depot farm and graduated from the Naval Academy in 1957, had a 9-year-old daughter and 7-year-old son when he was shot down in 1967.

The daughter, Ashlen Nunnery, today runs a UPS shop in Fleming Island, Fla.

Nunnery said her family didn't even know that Leo was alive until 1971. His picture was in an edition of Life Magazine, in a story about the POWs.

She idolized her father and still has his POW pajamas and sandals, as well as his retirement uniform and service revolver. It was a confusing and terribly trying time for the families and wives, she said.

She sees how it must have been excruciating for the POWs to find out their wives had remarried, and also extremely hard for the women left alone not knowing whether their husbands were alive.

"If there is a story to be told it's the families, the kids and the wives," she said.

Collings said that story is told in the exhibit.

The American military typically did not know if men from shootdowns survived.

Letters went out to families reporting them as missing in action.

Wives and mothers undertook a campaign for more information about their husbands or sons, whether they were alive and where they were and in what condition were they in, Collings said.

'How awful war is'

The design of the well-known POW/MIA flag was paid for by a family of a POW.

Millions of Americans owned POW bracelets, engraved with the names, ranks of POWs and those missing in action.

Later, around 1970, the POWs were allowed to receive mail.

POW McGrath told Collings that when he returned it had been eight years for his wife, but, for him, it had been essentially no time, as if time had stood still for those eight years.

The couple and family had to get to know one another again.

"When people see the black (POW) flag flying around on all the flagpoles, it is hard to truly understand what that flag means," Chaney says.

Ultimately, the immersive exhibit and others in the enormous museum filled with tank and plane exhibits drive home the horrible consequences of going to war.

"As we are spinning around on this little blue marble in the blackness of space, it is times like this that we truly hope that people realize how awful war is," Chaney said.

tdate@northofboston.com

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