Seventy-five years after Jack Lewin was liberated from the Auschwitz-Birkenau concentration camp, the specter of anti-Semitism is rising once again.

Recent violent attacks on Jewish Americans in Pittsburgh, Poway, Jersey City have left the 93-year-old Holocaust survivor shocked and angry.

I didnt believe that in my lifetime, we would have a repetition of what happened almost 80 years ago, Lewin told HuffPost.

Hundreds of Holocaust survivors from around the world are traveling to Auschwitz-Birkenau to commemorate the 75th anniversary of the death camps liberation on Monday, a date the United Nations has set apart as International Holocaust Remembrance Day. Over 45 world leaders gathered at Jerusalems Yad Vashem Holocaust memorial on Thursday to denounce the modern-day rise of anti-Semitism. Additional ceremonies are expected to take place on Monday at Auschwitz-Birkenau.

The Nazis used forced labor to turn an abandoned military base near the town of Owicim, in German-occupied Poland, into a sprawling prison complex and killing center. Families from across Europe were deported to Auschwitz-Birkenau in cramped cattle trains. Some were selected as forced labor, while others deemed too weak to work older people, women, children, the sick were killed in gas chambers.

Auschwitz was liberated by the Soviet army on Jan. 27, 1945. Between 1940 and 1945, more than 1.1 million people were murdered there , most of whom were Jews. In total, about 6 million European Jews perished during the Holocaust, effectively a third of the worlds Jewish population.

Decades later, Jewish communities in Europe and the U.S. have been alarmed by an uptick in anti-Jewish violence, harassment and vandalism, as well as a rise in Holocaust denial .

Tel Aviv University researchers recorded nearly 400 violent attacks against Jews worldwide in 2018, with the most dramatic spike occurring in western Europe. More than a quarter of the major violent cases that year occurred in the U.S., including a deadly massacre at Pittsburgh s Tree of Life synagogue that killed 11 worshippers. Jewish institutions have been targeted with threats , vandalism , arson and protests . More recently, attacks on Hasidic Jews in the New York-New Jersey region including a shooting at a kosher market and a stabbing at a rabbis home have raised alarms.

The Anti-Defamation League has also documented an increase in anti-Semitic rhetoric on social media and at schools .

As the 75th anniversary of Auschwitzs liberation approaches, HuffPost asked three Holocaust survivors to share their reflections on the modern rise of anti-Semitism and to offer wisdom to those who want to stop this hatred from spreading.

Jack Lewin