In a city filled with grand monuments to a tragic past, some here say the tiniest are the most powerful: the thousands of brass-topped cobblestones that are spreading over Berlin’s sidewalks.

Six new ones showed up on one street the other day. Five more on another. Each one marks a victim of the Holocaust, placed in front of that person’s home. Together they form an expanding constellation of lives that were lived in this city before it turned against its own.

This elegant capital has a grim, concrete-slab memorial covering five acres next to the Brandenburg Gate that is used for official events to commemorate the 6 million Jews who died in the Holocaust. But now, thousands in Berlin have their own markers, placed there by an artist who has installed similar stones across Europe.

The blocks, which artist Gunter Demnig calls stumbling stones, have spread across Germany at a time when the country’s basic relationship with its past has quickly been changing. Even the grandparents of many schoolchildren were born after World War II. The country’s postwar bonds with Israel, once unchallenged, have been fraying as more people question whether they have any special obligation to atone for the sins of their ancestors.

But the stones can still provoke powerful reactions. On a recent drizzly afternoon, groups of people greeted Demnig as he laid more than a dozen new stones around Berlin.

“This is the exact opposite of what the Nazis wanted,” said Thomas Berens, 46, a building manager in the Hansaviertel neighborhood of Berlin, which was leveled by bombing during World War II. At least 1,030 Jews in this area of less than a quarter square mile were killed by the Nazis, and Berens has been part of efforts to research the lives of some of the victims.

“Here it’s bringing back the names,” Berens said, as he waited for Demnig to pry up a pavement stone and replace it with six blocks, each with a name on it, along with a birthday and information about deportations and deaths. When they were sent to Auschwitz, the youngest in the family was 3 years old. The eldest, Margarete Hartstein, was 51.

Demnig, 65, who was born in Berlin shortly after World War II ended and who often wears a black-denim-and-leather outfit reminiscent of Indiana Jones, has made laying the stones his full-time work since 1997. Locals and family members commission them for $160 each, and the waiting list to install them now stretches two years. So far, 38,000 are scattered across Europe.

“They read in a book, ‘6 million,’ that’s abstract,” Demnig said. “But they see one family, they really think about what happened. They read, ‘He was as old as me, and he was murdered.’”

The stones stir passions far out of proportion to their size. Other cities have banned them, including Munich, Germany’s third-largest city, in part because local Jewish organizations objected to them. On the Nov. 9 anniversary of the 1938 Kristallnacht pogrom, all the stones in the northeastern town of Greifswald disappeared overnight. Authorities suspect far-right groups.

Some Jewish groups say the memorials are insensitive, leaving the dead to be trampled underfoot and leading Germans to focus exclusively on victimhood rather than considering how a civilized society could start killing its own citizens on an industrial scale.

“It’s very easy through this identification with the victims to overlook the larger framework of who killed them and who were the perpetrators,” said Deidre Berger, the director of the Berlin office of the American Jewish Committee.

But some victims’ descendants are also involved in assembling the stumbling stones. For many families, the monuments are the closest thing they will get to a physical memorial, since there are no cemeteries for the victims, whose remains were carried away as ashes by the winds above Auschwitz and Treblinka. Demnig says the markers are not intended as gravestones. To many onlookers, though, there are similarities.

Rivka Alexander, 62, traveled from the Netherlands with her family late last month to watch Demnig install stones for her grandmother and eight other relatives in front of a white, spare building in the Kreuzberg neighborhood of Berlin where her father grew up.

“He loved this city, and then they had to flee,” she said.

For some onlookers old enough to remember World War II, the small ceremonies were a moment to reflect on who caused the many deaths.

“We’re not personally responsible,” said Gerhardt Nyhuis, 76, who came to watch stones being laid for two victims next to what is now a subway station. But “it’s terrible what we Germans did.”

Petra Krischok contributed to this report.