Millions of records of people who were displaced or persecuted in the Holocaust are now available to search online for free.

The records have been digitised by Ancestry, a genealogy and DNA testing company.

Numerous genealogists have since flocked to the site to try to fill in long-standing gaps in family stories.

Rachel Silverman, a private genealogist specialising in Jewish family history, said she was enthusiastic about the development, but added that it was too early to know how useful the records would be.

“Every American Jew has people they lost,” she said. “It’s just the matter of the degree of separation.”

Remembering the Holocaust Show all 16 1 /16 Remembering the Holocaust Remembering the Holocaust 80,000 shoes line a display case in Auschwitz I. The shoes of those who had been sent to their deaths were transported back to Germany for use of the Third Reich Hannah Bills Remembering the Holocaust Barracks for prisoners in the vast Auschwitz II (Birkenau) camp. Here slept as many as four per bunk, translating to around one thousand people per barracks. The barracks were never heated in winter, so the living space of inmates would have been the same temperature as outside. Hannah Bills Remembering the Holocaust Hannah Bills Remembering the Holocaust Sign for the Auschwitz Museum on the snowy streets of Oswiecim, Poland Hannah Bills Remembering the Holocaust The Gateway to hell: The Nazi proclamation that work will set you free, displayed on the entrance gate of Auschwitz I Hannah Bills Remembering the Holocaust A disused watchtower, surveying a stark tree-lined street through Auschwitz I concentration camp Hannah Bills Remembering the Holocaust Stolen property of the Jews: Numerous spectacles, removed from the possession of their owners when they were selected to die in the gas chambers of Auschwitz Hannah Bills Remembering the Holocaust A sign bearing a skull and crossbones barks an order to a person to stop beside the once-electrified fences which reinforced the Auschwitz I camp Hannah Bills Remembering the Holocaust The peace and the evil: Flower tributes line a section of wall which was used for individual and group executions Hannah Bills Remembering the Holocaust Life behind bars: Nazi traps set to hold the Third Reich’s ‘enemies’. In Auschwitz’s years of operation, there were around three hundred successful escapes. A common punishment for an escape attempt was death by starvation Hannah Bills Remembering the Holocaust Burying the evidence: Remains of one of the several Auschwitz-Birkenau gas chambers Hannah Bills Remembering the Holocaust Hannah Bills Remembering the Holocaust The three-way railway track at the entrance to Auschwitz-Birkenau camp. This was the first sight the new camp arrivals saw upon completion of their journey. Just beside the tracks, husbands and wives, sons and daughters and brothers and sisters were torn from each other. Most never saw their relatives again Hannah Bills Remembering the Holocaust A group of visitors move through the Auschwitz-Birkenau camp. Viewed from the main entrance watchtower of Auschwitz-Birkenau Hannah Bills Remembering the Holocaust "The Final Solution": The scale of the extermination efforts of the Nazis at Auschwitz-Birkenau can be seen by comparing the scale of the two figures at the far left of the image to the size of the figure to the left of the railway tracks' three point split Hannah Bills Remembering the Holocaust Each cattle car would transport up to one hundred people, who could come from all over Europe, sometimes from as far away as Norway or Greece. Typically, people would have been loaded onto the trucks with around three days food supply. The journey to Auschwitz could sometimes take three weeks. Hannah Bills

The release includes passenger lists of millions of displaced people, including Holocaust survivors and former concentration camp inmates, who left ports and airports in Germany and other parts of Europe from 1946 to 1971.

It also includes records of millions of people with non-German citizenship who were incarcerated in camps or otherwise living in Germany and German-occupied territories from 1939 to 1947.

The records will not tell people who they lost in the Holocaust if they do not already have an inkling.

Instead, the records could provide additional hints at why a relative took one escape route instead of another, Ms Silverman said.

“In genealogy, the almighty why is the hardest,” she said. “Why did my family end up in Atlanta when they were from the small town in Germany? When we find out how travel was arranged, that might open new doors.”

Allan Linderman, from California, had researched his 87-year-old cousin’s journey to the United States before the documents’ release. Born in Poland in 1932, the cousin, Irving Rock, and his family fled their home in the early 1930s.

They then spent more than a decade scrambling for safety, moving from one place to the next. Because he is still alive, Mr Rock offered some details from memory. But in the trauma and chaos of relocation, he could not recall when precisely he left Germany for the United States.

Searching the new collection, using the original spelling of his name — Icek Rak — Mr Linderman found his cousin. The ship departed Bremerton, Germany, for New York on 7 September 1949.

Beyond curiosity, this information is useful, Mr Linderman said. The German government and Dutch Railway offer some financial compensation to victims. But they require documentation.

“This is another step in trying to get some reparations,” he said. “These are people who cannot prove the things that the German government requires because they spent all this time hiding.”

Both collections were drawn from the Arolsen Archives, a long-standing collection maintained by the International Center on Nazi Persecution. A portion of the archives was previously digitised. Yad Vashem, the World Holocaust Remembrance Center, also maintains digital archives.

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Ancestry maintains one of the largest databases of DNA profiles and family history data in the world, making more than $1 billion in revenue in 2017 alone, according to the company site.

Its financial model is built on getting millions of people to subscribe to its family history sites and pay for its DNA tests.

Ms Silverman said she had a client who wants to trace the path of his grandparents to Canada from Germany. She searched the new database and came up empty-handed.

She did find something that showed which congregation paid for the journey, but it was in the subscription database.

Successful or not, at least these searches don’t require travel or waiting for months for overstretched archivists to manually pull something up, said Marlis Humphrey, the former president of the International Association of Jewish Genealogical Societies.

In the past, Ms Humphrey has flown to Israel from Florida to look for records.

“This is unbelievable,” she said. “We can get the records in our pyjamas, and if we didn’t search right the first time, we can search again.”