On Christmas Eve 1972, Vietnamese translator Duong Tuong pushed his scratchy recording of a Sibelius violin concerto to full volume to drown out the wail of air-raid sirens over Hanoi.

"The B-52s were very punctual, always arriving at around 8 o'clock in the evening," Tuong, now in his 70s, said in an interview at his home in Vietnam's capital. "Music helped me get through it. Sibelius comforted me."Now, pop Christmas jingles and breathy Vietnamese love songs are more common in fast-changing Hanoi than Sibelius and sirens.

But for Tuong, like other residents old enough to remember, Christmas brings memories not of family reunions and holiday cheer but of bombs dropping from the sky as the United States mounted the most concentrated air strikes of the Vietnam War.

The so-called Christmas bombing of 1972 was a key U.S. air campaign in the war's waning days. More than two decades later, full reconciliation continues to elude Hanoi and Washington, and Christmas becomes a time of heroic memory for Vietnam's capital.

"What would Hanoi be like if, at the end of 1972, the U.S. B-52 squadrons had been allowed to spray their bombs and then leave unpunished?" the army's Quan Doi Nhan Dan newspaper said in an article commemorating the event, saying Vietnam had turned back an "ultimatum" delivered by U.S. bombers.

Operation Linebacker Two, involving thousands of sorties by American aircraft, rained 40,000 tons of explosives down on the northern Vietnamese cities of Hanoi and Haiphong for 11 days beginning Dec. 18, 1972 - excluding Christmas Day itself.

Do Dinh Dat, now 70, was deputy commander of the local street team in Hanoi's Kham Thien district, which took a punishing assault from B-52 bombing raids on Dec. 26.

Dat, pausing amid the throngs of people crowding the now-lively commercial district, said the memories were still fresh after more than two decades.

"While many people had been evacuated, a lot of Kham Thien people came back for Christmas Day," he said. "My family came back, and we were all here."

The next day the bombs started falling, blowing the roof off Dat's house and flattening a three-story house just across the street - killing three dozen people in minutes.

"We rushed out to see who we could save. We tried to dig through the wreckage to pull people out," Dat said. "It took us two weeks to clear the rubble. More died than I can count."

Vietnam's official statistics say 1,318 people died in Hanoi during the Christmas bombings, with more than 200 dead in Kham Thien alone.

While the numbers pale beside the military casualties suffered by both sides during the long years of fighting, it marked an awakening for the capital.

"It was designed to demoralize," said Nguyen Khuyen, editor in chief of the Vietnam News, who covered the raids for the state news service and picked through the wreckage of Kham Thien.

"Material destruction was commonplace during the war. But the extent of casualties to the civilian populace was unbelievable."