BAD AROLSEN, Germany -- Wilhelm Thiem may be 72 but he celebrated his first real birthday in November.
Abducted in Poland by Nazi troops at age two, Thiem has spent most of his life on a painful journey, seeking to discover his true name and identity.
Until just a few months ago, the retired entrepreneur had not known his birth date, where he was born, what had happened to his mother or whether he had any other family members.
"I hardly knew anything about my personal history," Thiem said. "I always felt like an outsider, it was a feeling of not belonging in this world."
Thiem was raised by a foster parent in northern Germany who was appointed by the Nazis to take care of the young child. Thiem called her "Mrs. Huebner" but was later officially adopted and given her maiden name.
At age 12, Thiem learned that Mrs. Huebner was not his real mother. He started asking her about his past, wanting to learn more about his family, but his questions remained unanswered. For decades, his personal history remained a mystery.
Early last year, Thiem came across a newspaper article about the International Tracing Service (ITS), an organization that maintains a vast archive of files related to more than 17.5 million victims of the Holocaust and Nazi oppression.
"At first the ITS researchers told me that they could not find any documents with my name on them," Thiem recalled. "But then they contacted the Red Cross in Poland and in the end, there were some leads."
'Very emotional moment'
After several months of research, Thiem was informed that he had been born in Lodz, Poland, and that his birth name was Zbigniew Wilhelm Katmierczak.
For the first time in his life, Thiem held a birth certificate in his hands that gave him an identity.
"It was a very emotional moment," Thiem recalled. "Both my wife and I could not hold back tears."
Researchers revealed that his mother was also sent to Germany as a forced laborer but later returned to Poland. She eventually married a Frenchman and relocated to France.
Thiem was also told of a surviving aunt, who still lives in his Polish hometown.
He is now anxiously making plans for a trip to Lodz with his wife for a very special family reunion.
"I am hoping to learn more facts, maybe find other family members," Thiem said. "Maybe I can find traces of my mother and father. All of this is of huge interest to me, it means so much."
Established by Allies in the final days of the Second World War and originally run by the Red Cross, the ITS helps to uncover the fates of Holocaust victims and others who suffered under the Nazi regime.
The archive in Bad Arolsen is said to be the largest storage facility of documents related to the Holocaust. It includes 30 million documents in 16 miles of shelves housing information about Holocaust survivors, displaced persons, slave laborers and political refugees from former Eastern Bloc countries.
Over the past 50 years, the ITS has answered more than 10 million requests. About 1,000 search requests continue to trickle in to the archive monthly.
"Many people still do not know what has become of their loved ones," said Dr. Ingeborg Berggreen-Merkel from Germany's federal commission of culture. "Even decades after the end of the Holocaust and the war, there is this persisting uncertainty, which results from the fact that part of one's own history remains untold."
Visitors to the archive come into direct contact with the bureaucracy of mass murder.
Its meticulous records include concentration camp files, "deportation cards," patient records and a post-war index of non-German citizens. Its researchers plow through the stacks of yellowing paper, registering and scanning as many of the historic documents as possible. More than 95 percent have now been digitized.
But due to concerns about the victims' privacy, the ITS and the German government kept the files closed to the public for half a century. While search requests have been accepted since the end of the war, the archive was initially not "open source."
Following public pressure from survivor groups, historians and researchers, who called for public access to the archives, the ITS Commission -- consisting of 11 member states -- declared itself in favor of opening up Bad Arolsen in 1998.
Yet, scholars and researchers were only given access to the documents beginning in 2007.
"I think it was criminal that the documents were not opened up earlier," said Holocaust survivor and U.S. judge Thomas Buergenthal. He was able to find records of his father's ordeal in the concentration camps of Auschwitz, Sachsenhausen and Buchenwald at Bad Arolsen.
"This archive is my father's only memorial, we have no other," Buergenthal added.
But although time has claimed many eyewitnesses, the archive is still helping to reunite survivors of Nazi terror -- such as Thiem and his long lost aunt. She remembers her nephew -- who is now an elderly man -- as a "little child."
"I spent a lifetime wondering who I really am, now I know," Thiem said.