When folk singer Joan Baez hunkered down in the air-raid bunker beneath Hanoi’s Metropole Hotel in the days around Christmas in 1972, she listened as B-52 bombs hammered the city.

Earlier this month, she returned, forty years later, after hearing that the shelter in which she cowered from the American bombers, and recorded material for her album Where Are You Now, My Son, had been excavated.

“Something in me was ready to come back,” she told AP from her suite in the hotel during her visit earlier this month.

Her stay in Hanoi from March 27 to April 6, was her first visit to Vietnam since she travelled in December 1972 as a member of a peace delegation from the United States during the Vietnam War.

On her visit this month, Baez spent time with the hotel staff who remembered her from her earlier visit, as well as visiting a local international school and speaking to the children and re-visiting the bunker.

She also left behind a souvenir for the hotel: a portrait of a Buddhist monk that she painted herself during her stay. It now hangs in the main lobby.

She met with staff who’d worked at the hotel during her 1972 visit, including the housekeeper, Tieu Phuong.

According to AP, Phuong said she remembered Baez, as well as American pilots who were released from Hanoi prison and stayed at the hotel before returning  home to the United States.

During her time hiding in the bunker in 1972, Baezrecorded air-raid sirens, bombs and the voices of her companions, sounds which would comprise one side of her album.

She also recorded the sound that would lend its name to the title: a woman wailing “Where are you, my son?”

However, on her revisit to the bunker, Baez said she felt only “love” for the shelter.

“What I felt was this huge warmth, and it was gratitude,” Baez told AP, describing her return to the shelter. “I thought I’d feel all these wretched things about the bunker, but it was really love. It took care of me, and so I didn’t have any problem going back.”

The American singer, who once dated Bob Dylan, has recorded more than 50 albums, most recently a 2008 record produced by Steve Earle, titled Day After Tomorrow.

But she is almost as well-known for her social activism.

In the early years of her career, she was vocal in the anti-Vietnam War protest as well as the civil rights movement.

Since then, Baez, who considers herself a pacifist, has lent her voice to causes including the anti-Iraq war protest, poverty, human rights and equality for the gay and lesbian community.

During this year’s visit, a private trip, she reminded a group of schoolchildren at a local international institution of her act of defiance at 16: when she refused to leave her school in California to go home during an air-raid drill.

According to AP, Baez first contacted the hotel about a visit when she read news reports about the re-opening of the bunker.

The hotel itself, Sofitel Legend Metropole Hanoi, opened in 1901 and has since hosted numerous celebrities, including legendary comedians and novelists.

It was renovated in 2009, and its Metropole Wing features suites named for famous guests such as Charlie Chaplin, Somerset Maugham and Graham Greene.