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.

After his deposition as mayor by the Germans in 1941, Gaston Ooms joined the resistance. He was betrayed by collaborators in 1943 during one of his actions and arrested by the Germans. After a few prisons, Hasselt, Sint-Gillis, he ended up in the concentration camp of Flössenburg. There he died of exhaustion on March 6, 1945.

He was a member of the resistance group of the Partisans PA 035 Limburg, is transferred to Breendonk after the prisons of Turnhout and Hasselt where he becomes acquainted with inhuman torture in the "Bunker" to die on the execution post on April 11, 1944 after being sentenced to death , along with 22 others, will be hung on the 24th. He was just under 21 years old. 

After his remains were found, he was reburied in the cemetery of Beverlo after a ceremony in Hasselt on December 15-18, 1945.

He was a deputy to the PA leader. Convens also ended up in Breendonk after a German raid via the Hasselt prison, also after inhuman torture. He dies on the execution stake along with 22 others, the 24th is hanged, on April 11, 1944. He had just turned 21. After his remains were found, he was reburied in the cemetery of Korspel 15-18 December 1945 after a ceremony in Hasselt under mass interest.

Albert Huybrechts was a member of the resistance during the Second World War and was involved in a notorious train derailment in North Limburg. The Germans must have known something, because a few days later they surrounded the football field of Red Star Korspel, where a match was taking place. The raid resulted in several arrests. Albert fled through the surrounding woods but encountered German guards, who shot him.