In a concrete bunker under Hanoi's most prestigious hotel, the voice of American folk singer Joan Baez pierces the dank air. From a fuzzy tape recording comes her famous anti-war song, Where Are You Now, My Son, which she wrote and partially recorded in this cramped and sweltering air-raid shelter. The music is punctuated by the crump of bombs hitting the ground above.
Joan Baez stayed at the Metropole hotel over Christmas in 1972, when the US Air Force unleashed Operation Linebacker II, its most intensive bombing campaign since World War II.
With a couple of other peace activists, including Telford Taylor who was counsel for the prosecution at the Nuremburg Trials, and hotel staff, she spent every night of the 11-day bombardment crammed with up to 40 people in this small network of dark cells under the hotel's back courtyard.
The entry stairwell was sealed after the war and the bunker forgotten for 37 years, to be unearthed two years ago during renovations to a terrace bar and pool. Now, small groups go into the bunkers to relive history.
As the temperature inside soared to 40 C, Baez would play guitar and sing to keep terror at bay. Where Are You Now, My Son refers to the cries of a woman Baez saw one morning searching for her son lost under rubble from the night's raids.
The singer and human rights activist remains a heroine at the hotel, now called the Sofitel Legend Metropole Hanoi and considered one of the grandest hotels of Asia. It feels like Baez is a constant presence there, although she has made only two visits in her 73 years. The first was during the failed attempt to demoralise the North Vietnamese in 1972.
The second visit was last year and, like the Christmas bombings, it lasted 11 days. Baez went back into the reopened bunkers. The hotel manager reports she touched a clammy concrete wall and quietly sang the American civil rights song Oh Freedom.
For the Metropole management and staff, the return of Joan Baez was a legend come to life. The history and mythology of their workplace is steeped in stories of how this American woman stood alongside them during the American War, as the Vietnamese refer to the conflict we call the Vietnam War.
Photographs and mementoes of her wartime visit are in a Path of History display in the lobby. A piece of shrapnel the singer had taken from a bomb crater in 1972 and returned in 2013 is in a display case. She believed it was the shape of a vulture.
The hotel bar offers a Joan Baez cocktail. And, near the reception desk, is an oil painting of a Vietnamese boy, a novice monk. It was painted by Baez in the Somerset Maugham suite of the Metropole last year She told the manager her voice was not so good these days, so she'd taken up painting.
The Metropole, built and named in 1901, became the Reunification Hotel under the communist government and was used as a guest house for international visitors and diplomats. It became a private hotel again in the 1990s.
Only the hotel's guests can explore the bomb shelters. It is difficult to open the bunkers to wider tourism because of their location under the bar and pool.
A local historian is damp-eyed as she explains the impact Baez had, and still has, at the Metropole. During the American War, she explains, Baez more than any other Westerner bravely stood alongside the North Vietnamese, speaking loudly in international protest and dodging bombs with the locals.
Between air raids she visited American prisoners of war at Hoa Lo Prison (the infamous Hanoi Hilton) and delivered mail from home.
It is unlikely Baez met Senator John McCain, America's most celebrated prisoner of war, who would probably have been applauding the Christmas bombings from the Hanoi Hilton. But McCain is another return visitor to Hanoi, staying at the Metropole, and he is welcomed warmly and forgivingly, in the fashion that seems to be the general attitude of many Vietnamese towards Americans.
Actor Jane Fonda, the infamous Hanoi Jane, seen as a traitor to her homeland during the war, also stayed at the Metropole in 1972, before the bombings, and she, too, has made return visits.
Actor Michael Caine is another former guest, there for the filming of The Quiet American. Writer Graham Greene, like Somerset Maugham, has a suite named in his honour. He wrote parts of The Quiet American at the Metropole. And Catherine Deneuve stayed to film Indochine.
Vladimir Putin has been a Metropole guest and so have Brad Pitt, Angelina Jolie, and Mick Jagger. But no one is so warmly welcomed or sadly farewelled as Baez.
And no one else has the first painting they have put their name to hanging proudly in the lobby.
Joan Baez is touring New Zealand in October. See here for more information.