On Monday evening as the sun sets and the  27th day of the month of Nisan begins, Jews around the world will be commemorating the somber Yom HaZikaron laShoah ve-laG’vurah (Holocaust and Heroism Remembrance Day), or, as it is generally called, Yom Hashoah. On this day, we remember the approximately six million Jews murdered in the Holocaust by Nazi Germany and its collaborators, and for the Jewish resistance in that period. 

Here are five things you may not have known about Yom Hashoah and the Holocaust.

1: Yom Hashoah was almost a different day

The first Yom Hashoah was commemorated on December 28, 1949. This was the 10th of Tevet, a day of mourning and fasting in the Hebrew calendar. The day was marked by the burial in a Jerusalem cemetery of ashes and bones of thousands of Jews brought from the Flossenbürg concentration camp and religious ceremonies held in honor of the victims. 

Other days that were considered by the Knesset for commemorating the Holocaust were the 14th of Nisan, which is the day before Passover and the day on which the Warsaw Ghetto uprising (April 19, 1943) began, and September 1, the date on which the Second World War began. 

In 1951, after some deliberation,  the Knesset passed a resolution establishing the 27th Nisan, a week after Passover, and eight days before Israel Independence Day as the annual Holocaust and Ghetto Uprising Remembrance Day.

The United Nations designated January 27 as International Holocaust Remembrance Day. The date marks the liberation of the Auschwitz-Birkenau death camps in 1945.

Some ultra-Orthodox Jews commemorate the Holocaust on Tisha B’Av (the ninth of Av), the day commemorating the destruction of the Jewish Temples and other national tragedies. This is because, in Jewish tradition, the month of Nisan is considered a joyous month associated with Passover and messianic redemption. 

Observance of the day is moved back to the Thursday before, if 27 Nisan falls on a Friday, or forward one day if 27 Nisan falls on a Sunday. The fixed Jewish calendar ensures 27 Nisan does not fall on Saturday.

2: Israel comes to a total standstill

Every year, at 10:00 AM on Yom Hashoah, sirens across Israel sound for two minutes, bringing everything in Israel to a complete standstill and Israelis stand in silence. Cars on highways come to a stop as the occupants step out to stand at attention by the side of the road.

3) Four holidays with one national message

A series of significant days begins with the seven days of Passover beginning on the 14th of Nisan, celebrating the birth of the Jewish nation. One week after Passover ends, Jews commemorate Yom HaShoah. One week later, on the 4th of Iyar, Israel observes Yom HaZikaron LeHalelei Ma’arkhot Yisrael ul’Nifge’ei Pe’ulot HaEivah ( ’Memorial Day for the Fallen Soldiers of the Wars of Israel and Victims of Actions of Terrorism). Known colloquially as Yom HaZikaron, the day commemorates the battle for modern Israel that began less than three years after the Holocaust ended in 1945. The next day, Israel shifts from mourning to joy as we celebrate Yom Haatzmaut, commemorating the Israeli Declaration of Independence in 1948.

Understood as a series, the four days commemorate the return of the Jewish people to our Biblical homeland.

4) Jewish population has still not recovered

Jews are a tiny minority. There are currently about 14 million people around the world who self-identify as Jewish, representing 0.2% of the global population. But this was not the case before World War II. 

In 1939, the global population of Jewish people worldwide peaked at around 16.6 million. According to the American Jewish Yearbook, the Jewish population of Europe was about 9.5 million in 1933 representing about 60% of all the Jews. After the Holocaust, the Jewish population of Europe was about 3.5 million, about one-third of the post-war global Jewish population. Most Jews (51 percent) lived in the Americas after the war. 

By 1945, most European Jews—two out of every three—had been killed.

A World Jewish Population report in 2020 stated that the Jewish population stood at 15 million; still well below pre-Holocaust levels. This is even more worrying when considered in context. In 1939, the world population stood at two billion, more than tripling by 2015, reaching 7.4 billion. 

The Jewish population is still much lower now than it was before the Holocaust and the population of the Jews in Europe has been in decline for several decades. 

One study carried out by Professor Sergio DellaPergola, perhaps the most well-known expert in Jewish demographics in the world today, suggested that had the Holocaust not taken place, the global Jewish population would have been at least 26 million and possibly as much as 32 million today.

The good news is that the number of Jews in Israel today has surpassed the tragedy of the Holocaust, standing at over seven million.

5) The Hidden Jews of Poland

Prior to the outbreak of World War II, Poland was home to the largest Jewish population in the world, hosting more than 3,000,000 Jews. Poland was (and still is) a Catholic-majority nation. But it was bordered by Lutheran Germany and Orthodox Russia. According to some reports, forty-four church orders and 350 monasteries were active in Poland on the eve of World War II, with a population of 6,430 monks; thirty-four communities of nuns maintained 2,300 institutions in which 22,000 nuns served, though these numbers dropped significantly during the war.

Before the war, about 400 convents across Poland had institutions for children. The Vatican was unsympathetic to the Jewish plight during the Holocaust and sheltering Jewish children placed all Christian inhabitants of the convent in mortal danger, requiring them to share their scanty provisions. From the Jewish side, few Jewish parents were willing to entrust their children to Catholic institutions. Some suspected the Catholic clergy of wanting to exploit the Jews’ agonies in order to convert their children.

Some Jewish children did enter these orphanages in a desperate attempt to save them from the Nazi onslaught. Ninety percent of Polish Jewry was annihilated in the Holocaust, and post-war Communist oppression caused many of Poland’s remaining Jews to flee. Those who stayed often had to hide their identities. Their children, raised as Polish Catholics, many have only recently learned of their true Jewish identity.

One notable exception was the Kindertransport, which took in over 10,000 Jewish children from Austria, Czechoslovakia, and Germany and brought them to safety in England prior to World War II.  

Among the conditions of participation, children would be accepted only up to the age of 17, and only without their parents, many of whom perished subsequently in the Holocaust (only about 40% of survivors were reunited with parents after the war). 

Few of the children converted to Christianity.