Information: Wikipedia

A Stolperstein literally "stumbling stone", metaphorically a "stumbling block" is a sett-size, 10 by 10 centimetres (3.9 in × 3.9 in) concrete cube bearing a brass plate inscribed with the name and life dates of victims of Nazi extermination or persecution.

The Stolpersteine project, initiated by the German artist Gunter Demnig in 1992, aims to commemorate individuals at exactly the last place of residency—or, sometimes, work—which was freely chosen by the person before he or she fell victim to Nazi terror, euthanasia, eugenics, was deported to a concentration or extermination camp, or escaped persecution by emigration or suicide. As of 29 March 2018, over 67,000 Stolpersteine have been laid in 22 countries, making the Stolpersteine project the world's largest decentralized memorial.

The majority of Stolpersteine commemorate Jewish victims of the Holocaust. Others have been placed for Sinti and Romani people (then also called "gypsies"), homosexuals, the physically or mentally disabled, Jehovah's Witnesses, black people, members of the Communist Party, the Social Democratic Party, and the anti-Nazi Resistance, the Christian opposition (both Protestants and Catholics), and Freemasons, along with International Brigade soldiers in the Spanish Civil War, military deserters, conscientious objectors, escape helpers, capitulators, "habitual criminals", looters, and others charged with treason, military disobedience, or undermining the Nazi military, as well as Allied soldiers.

List of Stolpersteine in the city of Herentals

Markgravenstraat 93: HENDRIK AERTS    

                                       JOZEF AERTS

St.Waldetrudisstraat 96: LEON PUYENBROEK

During the war, Jozef and Hendrik join the secret army. They call themselves the Belgian Tommies, a resistance group whose task it is to collect information about the doings of the occupying forces and to smuggle shot down allied pilots out of the country. 

On March 16, 1943, Jozef Aerts was taken from his house in the Markgravenstraat at 4 o'clock in the morning by the Gestapo. He is transferred to the prison in the Begijnenstraat in Antwerp, where he is severely beaten by two of his fellow townsmen T. and E. Jozef knows them all too well: T. was with the Belgian Tommies, just like him, but now it appears that it is he who betrayed him. For sixteen days he is folded in Antwerp by the two. 

Jozef Aerts is sentenced to death on August 18. At the beginning of October 1943 he was put on a transport to Essen, in February 1944 he arrived in the German camp of Esterwegen, to end up in the concentration camp of Flossenburg in March 1945. There he is sent on a death march with 750 fellow sufferers. Jef had a paralyzed leg, due to childhood paralysis. It is impossible to imagine how he completes that death journey. In the end, 200 of the 750 prisoners remain, the rest die of deprivation. For Jef the story ends on April 12, 1945, he is hanged in an army barracks in Offenburg. 

Hendrik Aerts suffers the same fate a few months after the arrest of his four-year older brother, on 19 June 1943. He is also mistreated in the prison in the Begijnenstraat. On August 12, he is transferred to the concentration camp of Gross Rosen in what is now Poland, where he has to do slave labor in the huge quarry near the camp. The prisoners at Gross Rosen lived an average of 60 days. Hendrik succumbs on December 18.

In memory of professional soldier Léon Puyenbroek (1899-1945 Ohrdruf), who was arrested on 19 June 1944. He had joined the Kempisch Legion and actively assisted Allied pilots who had been shot down.  He was arrested on 14 July 1944 by the Sicherheitsdienst and deported, first to Buchenwald and then to the Ohrdruf concentration camp, south of Gotha in Thuringen. Every trace ends there. Ohrdruf was liberated on April 4, 1945.

The family chose April 4, 1945 as the symbolic date of death.