JERUSALEM (AP) _ Scrawled on a strip of tape is a message written by a 12-year-old boy to his mother in another part of Germany's Stutthof concentration camp: ``Don't worry about me ... We will soon be together again.''

The letter is one of the thousands of documents collected by Israel's Holocaust museum, where curators marking the start of Holocaust Memorial Day on Monday evening said they hoped aging survivors would continue to donate items that tell individual stories.

Since 1955, the museum has collected about 2 million pages of testimony from survivors, among 50 million pages of documents.

There are artifacts like the striped clothing worn by prisoners in Nazi camps.

And there are letters like the one written in pencil on a yard-long piece of tape by Siegfried Rapaport to his mother. In it, young Siegfried promises he'll send her bread if he gets some and tells her he hopes her stomach no longer hurts.

Some letters were written by Jews on their way to concentration camps, thrown from train windows in hopes that someone might find them. Some were written in code. Others were final, dying words, written to children, husbands, wives.

``I did not love anybody in the whole world as much as I loved you,'' wrote Regina Kandt, from Belgrade, Yugoslavia, to her husband.

Sifting through the documents, archivists at the Holocaust Museum worry the stories will be lost to history.

``There are a lot of stories that will be lost,'' said Yakov Lozowick, director of Yad Vashem's archives. ``Most survivors were not interviewed.''

Siegfried's letter to his mother ``is an incredibly powerful piece of testimony, precisely because this boy in his innocence manages to transcend the place where he is,'' Lozowick said.

Varda Cohen, 77, Siegfried's sister and the only surviving member of the family, still cries when she reads it. Her voice thickens and tears form under her glasses as she reads from the photocopy she made when she donated the original to the museum. She feels guilty because, by some wrinkle of fate, she wasn't in the camp.

Siegfried and Varda grew up in Hanover, Germany, with their two other siblings and parents.

They played with other Jewish children on Hohenuffer Strasse, or High Bank Street, which had a river bank on one side and on the other, a large gate they used as a soccer goal.

Then Hitler came to power, and the family was split. Their father was sent to a ghetto in Warsaw, Poland, and his letters eventually stopped arriving.

Varda was sent to England on a Kindertransport with other Jewish children. Before her mother and siblings could join her, they were sent to a ghetto in Riga, Latvia. Her youngest brother, Paul, was sent to Auschwitz, where he died.

Siegfried, his mother and another sister were sent to Stutthof camp in Germany. In his letter, Siegfried tries to calm his mother. ``Mother, be kissed,'' he writes. ``We will soon be together again, frying potatoes in the dressmaking salon.''

A short time later, Siegfried was sent on a death march.

``That was in deep winter, and he was never heard of again,'' Varda said.

The Russians liberated the camp, and two weeks later, Siegfried's mother died. Paula, the daughter who was freed with her, buried her in a field beside an abandoned farm house somewhere. No one knows where.

Decades later, Varda, who lives alone in Jerusalem, gave Siegfried's letter to the museum, worrying that it might otherwise disappear and be forgotten.

As she does each Holocaust Memorial Day, Varda remembers her family.

``I'm together with my family again completely,'' she said. ``I light candles for them.''