The voices of the Holocaust survivors were sturdy, even jaunty, as they sang for David Pablo Boder, a professor of psychology who interviewed 130 people at a displaced-persons camp in Henonville, France, in the summer of 1946. Now the “Henonville Songs” are being heard for the first time in 70 years, after being recently discovered inside a mislabelled container at the Cummings Center of the University of Akron.

On the Cummings Center blog, John Endes, a media specialist at the university, writes that he and his colleagues came across the recordings when they were sorting through Broder’s 1946 interviews. Among them included a spool that had been categorized as “Heroville Songs.” Realizing that an unfortunate typo might have obscured the recording of the long-lost “Henonville Songs,” Endes and his team set out to unlock its contents—a task that involved a bit of tinkering and considerable ingenuity, Cody Fenwick reports for Patch.

As Fenwick writes, when Boder went to Europe after the war, he taped his interviews on a wire recorder, a now-obsolete piece of technology. But though the university team had access to several wire recorders, none were the right fit for the spool. Determined to get at its contents, they decided to build a customized recorder by ordering a compatible model on eBay and upgrading it with new parts.

When the team was finally able to get the recording to play, they were greeted by the voices of several Holocaust survivors, who sang confidently in German and Yiddish. Some of these survivors performed tunes that they were forced to sing as they ran to and from work sites in forced labor camps.

“I think it is one of the most important discoveries from our collections in our 50-year history," David Baker, executive director of the Cummings Center, said in a press release. “That we could give the world the melody to a song sung by those sentenced to their death through forced labor during one of the most unspeakable horrors of the 20th century is remarkable.”

According to Voices of the Holocaust, a project devoted to the preservation of Broder’s interviews, Broder made his recordings to study the impact of acute trauma on people who had survived Nazi atrocities. But he also wanted to “preserve an authentic record of wartime suffering”—to ensure that the voices of survivors continued to be heard long into the future.

Since getting the spool to play, Endes and his team have now digitized the Henonville Songs, making them accessible to listeners around the world—a fitting end to the tale of the lost recording.