The storehouse of files on non-Germans persecuted and killed by the Nazis was officially opened Wednesday to all historians in the German town of Bad Arolsen, accordimg to the dpa.
The papers contain the names of most concentration camp inmates, forced-labour victims and refugees left homeless after World War II.
Digital copies of much of the archives have already been sent to the Yad Vashem Memorial in Jerusalem, the US Holocaust Memorial Museum in Washington and the National Institute of Remembrance in Warsaw.
The International Committee of the Red Cross (ICRC) began letting historians into the International Tracing Service (ITS) collection at Bad Arolsen earlier this year. Previously only survivors and close relations of the dead were allowed to see the papers.
Wednesday's official opening marks brought closure in a long and angry debate over keeping the files confidential.
Reto Meister, the Swiss Red Cross official in charge of the files, said in an interview in Bad Arolsen the files were the most potent answer to Holocaust deniers: "Anyone who wants to minimize the Holocaust should come here. We'll show him documents by the million."
The "overwhelming scale" of the card index was more persuasive than any debate, said Meister, adding, "Most of the documents were drawn up by the Nazis themselves." The collection of captured documents began in 1946.
Jewish groups led the campaign for open access to the files. Earlier custodians argued that they contained private information about individuals and must remain secret, but they were overruled by the 11 nations that legally own the document store.
"We have documents here about a horrifyingly wide range of victims: Jews and Christians, Eastern and Western Europeans, Germans and non-Germans, men and women. There's not one country where victims did not come from," said Meister.
So far the ITS has exported images of both sides of 9 million incarceration documents, 21 million cards from its main name index and 3.5 million papers in its displaced persons index.
Another block of documents relating to forced labour will follow in the summer, bringing scanning to 70 per cent of the paper documents. The entire archival holdings are expected to be digitized by 2011 so that it can be mirrored in all three capitals.
The US Holocaust Memorial Museum is leading efforts to start an all-new, computerized index to the images.