The first prisoners of the Auschwitz-Birkenau death camp arrived 80 years ago on May 20, the first of millions who would be condemned to endless labor and death at one of Nazi Germany’s most notorious concentration camps.

The first transport, according to the Holocaust Encyclopedia, consisted of about 30 German inmates whom the SS had categorized as "professional criminals." They had been selected for transport from the Sachsenhausen concentration camp near Berlin.

Between 1940 and 1945, the SS and police deported at least 1.3 million people to the Auschwitz camps. Of these, about 1.1 million people were killed. Auschwitz was liberated by the Soviet army on Jan. 27, 1945.

World leaders arrive in Israel to commemorate 75th anniversary of Auschwitz liberation

Survivors and families of Auschwitz recently marked the 75th anniversary of the camp’s liberation.

According to a study released on Holocaust Memorial Day in 2018, about two-thirds of American millennials do not know what Auschwitz is, according to The Washington Post. As memories of World War II continue to fade, researchers at the Conference on Jewish Material Claims Against Germany found that knowledge about the 6 million Jews killed by the Nazis is also fading, particularly among adults ages 18 to 34.

Twenty-two percent of millennials said they have not heard of the Holocaust or are unsure if they have heard about it.

The study relied on answers from 1,350 American adults in February, the Post reported. According to the study, 41% of the American adults and 66% of millennials were unable to correctly answer that Auschwitz was a concentration camp or a place where prisoners were exterminated, the Post reported.

Nazi Germany surrenders 75 years ago

New information on the victims and survivors of Nazi persecution has been added to what is already the world’s most comprehensive online database.

The Arolsen Archives–International Center on Nazi Persecution, formerly known as the International Tracing Service, has published 26 million documents to its database, including new information on forced laborers and deported Jews, according to Israel Hayom.

»MORE: 26 million documents now online on victims, survivors of Nazi persecution

The database was established by the Western Allies in 1944 and changed its name to Arolsen Archives in 2019.

All 26 million of the Arolsen Archives documents are now available online, including new information about 21 million people displaced, persecuted and murdered by the Nazis.

Archive officials said the recent addition to its online database was completed with its partner, Yad Vashem, Israel’s Holocaust memorial center in Jerusalem.

»MORE: Nazis surrender 75 years ago, ending World War II in Europe

“This means that the majority of the documents in the world’s most comprehensive archive on Nazi persecution are now accessible online,” the organization said in a statement. “They are a unique body of evidence that documents the crimes committed by the Nazis, and they are of immeasurable value to the relatives of the victims of Nazi persecution.”