Scattered throughout the streets of Germany (as well as in many other streets in Europe and in Russia) are so-called Stolpersteine:
These “stumbling blocks”, as they would be translated, are set in the ground in front of houses of victims of the Holocaust. They are not quite flush with the ground, but are instead raised a little bit higher, allowing one to stumble while passing by. Each mini monument is engraved with information about the victim and their fate. The 12 featured here are from Karlsruhe, and tell the stories of twelve representatives of Parliament who were forbidden from doing their jobs, arrested, deported, interrogated, sent to concentration camps, or any combination thereof.
I think these stones, designed and laid by German artist Gunter Demnig, are an amazing form of art. They are deeply meaningful, evoke many emotions, and preserve a dark history so that it cannot be obscured with time. They honor and commemorate. They bring about deep reflection in the viewer. You don’t have to go to a museum to see them; they confront you whether you want them to or not. I suggest reading the wikipedia article for more information. If you speak German, you can also read the Gunter’s site.