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 Wilsele

Jean Baptiste Van Monsstraat 65: HENRI BOLLENS

Henri Bollens was strongly committed to the socialist movement and became a Leuven city council member in 1921. He was arrested on December 23, 1943, for harboring resistance fighters and being an informant in the Partisan army. 

Henri worked at the Leuven metal factory Ateliers de la Dyle, where he joined the socialist trade union. In 1911, he became the first permanent secretary of the "Leuven Federation of Trade Unions." During the First World War, he participated in bread distributions for unemployed Leuven residents. After the war, he became chairman of the socialist mutual health insurance fund.  In addition to his union work, Henri was active in various social initiatives, such as the cooperative stores "De Proletaar" and the clothing union. He was a member of the Socialist Young Guard and was elected to the municipal council in 1921 for the BWP (Belgian Workers' Party). He supported the Republicans during the Spanish Civil War and campaigned for the Socialist Party during World War II.

During the occupation, he was active in the resistance. He safeguarded the funds of the Socialist health insurance fund and kept the cooperative store open. He was eventually arrested and deported to Breendonk and later to the concentration camps of Vucht and Buchenwald, where he died on March 1, 1945.