One of the little things that captured my attention when travelling—stolperstein.
A stolperstein or stumbling stone, is a concrete cube bearing a brass plate inscribed with the name and life dates of victims of Nazi extermination. The stolperstein art project was initiated by the German artist Gunter Demnig in 1992, and is still ongoing. It aims at commemorating individual persons 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 11 January 2015, over 50,000 plates have been laid in 18 European countries, making the stolperstein project the world’s largest decentralised memorial.
Read more here: https://en.wikipedia.org/wiki/Stolperstein