Sladek, who is Jewish, was younger than 10 years old when he and his family had to escape the Nazi roundups of Jews in his native Slovakia (which, at the time, was Czechoslovakia). Tragically, half of Sladek's extended family was killed during the Holocaust. Eleven of his cousins who were his age or younger perished in the genocide in which Nazi Germany killed approximately six million European Jews.

Sladek wants people to understand that the Holocaust "didn't happen overnight." To him, it kind of felt like slow motion.

"[The Nazis] took away all of our citizenship rights and slowly but surely they stripped us of everything," he said.

Sladek was able to survive after hiding out in the Tatra Mountains with his parents. In March of 1945, his family was liberated by a group of Russian soldiers. World War II ended about six months later.

After the war, Sladek and his family moved to Israel. After graduating high school, Sladek, who always loved music — his father, also a musician, used to sell instruments in his store — eventually served in Israel's entertainment corps, which Sladek likened to an Israeli version of the United Service Organizations (USO). 

Sladek eventually moved to the U.S. to be with his cousin in Los Angeles. It was in California that he met his future wife, who was from Colorado.

Today, 86-year-old Sladek lives in Denver. He has been speaking about his story of survival for more than 40 years.

"I always tell young people don't hate. Don't learn how to hate, because it's going to kill you in the end," he said. "That's one lesson I share with most young people."

Below, you can hear Sladek tell his story in his own words.

Jan. 27 is International Holocaust Remembrance Day, observed more than eight decades since the annihilation of six million Jews and millions of other Nazi victims began. The date is significant because it is a symbol of survival – it's the day that the Auschwitz concentration camp was liberated in 1945.

Many people believe that this 80-year-old history is more relevant than ever. Hate crimes are surging in the United States. There were more hate crimes reported in 2020 than in the previous 12 years. In 2022, there have already been multiple high-profile incidents in which Jews were targeted. Earlier this month, four people inside a Dallas-area synagogue were held hostage by an armed intruder. And in multiple cities across the country, including Denver, hate-filled pamphlets featuring antisemitic and anti-vaccine messages were recently distributed on people's front steps.

A survivor of the 2018 mass murder at the Tree of Life Synagogue in Pittsburgh, Barry Weber, spoke to NPR of the ongoing threat. “I keep on thinking of all the people […] that are not aware of how words can cause chaos. The Internet, the radio, the TV - the means of communications we have today are much broader than they were back in the days of Adolf Hitler, but Adolf Hitler was able to use words that stirred his people into hating our people. Words have caused chaos against the Jews and against other minorities.”

Sladek had a similar message to share with Rocky Mountain PBS.

“It’s almost like I have a duty to share with the world about the development, what happened before the round-ups of Jewish people in my town, in my country," he said. "And because most people have no idea […] I think it has a lot of value for people to understand how a genocide starts.”