A school in Poland unveiled a plaque Tuesday that commemorates 87 Jewish girls who were expelled in 1939 during the Nazi occupation of the country.

The event in Krakow is one in a growing number of efforts by teachers and children to commemorate the Jews who lived in Poland before the Holocaust, which was perpetrated by Nazi Germany largely in occupied Poland.

The event was held to mark the 125th anniversary of the founding of the No. 2 middle school in Krakow, which before World War II was an all-girls school.

Lital Beer, director of Yad Vashem's Reference and Information Services, said her researchers worked for nearly two years at the school's request to determine the fate of the 87 girls. She said 21 were killed in the Holocaust and 24 survived, but the fate of the others could not be determined.

The task of tracking down girls was made especially difficult due to the fact that many of them changed their names more than once, first taking on Hebrew names if they settled in Israel, and then changing surnames again upon marriage. It was not clear if any of the girls are still alive.

The research project began nearly two years ago when principal Gabriela Olszowska contacted Yad Vashem after finding a trove of records that included a list of the 87 Jewish girls expelled on Dec. 9, 1939, following orders from the German Nazi authorities.

Beer said Yad Vashem gets a lot of requests to do private research for individuals, and is usually not able to accommodate most of them, but gave special attention to this case.

"I was very moved by the principal's initiative to research the girls and commemorate them," Beer said. "We want to embrace those initiatives as much as we can."

Zvia Fried, who conducted much of the research for Yad Vashem, took part in the ceremony, saying by phone from Krakow that it was "very moving" and included prayers led by a rabbi and a Roman Catholic priest.