BERLIN — Germany is opening a museum exploring the fate of millions of Germans forced to leave eastern and central Europe at the end of World War II, along with other forced displacements of the 20th and 21st centuries — a sensitive project that has taken years to realize.

Chancellor Angela Merkel is due to speak to an opening ceremony Monday for the Documentation Center for Displacement, Expulsion, Reconciliation, more than 13 years after her government gave the plan the go-ahead. Housed in a late-1920s building in downtown Berlin, it features some 700 exhibits over 1,500 square meters (16,000 square feet).

Making the project reality was long viewed as "an impossible balancing act," said the center's director, Gundula Bavendamm, recalling "heated arguments about priorities and contextualization."

Controversies revolved around one central question, she said: "How can the exodus and expulsion of Germans at the end of and after World War II be portrayed without raising the slightest doubt that this country is aware of its lasting responsibility for the German crimes of World War II and the murder of European Jews?"

The project centers on the millions of Germans who fled from advancing Soviet forces or were kicked out of parts of eastern and central Europe as Germany's borders were moved westward after the war, "in the historical context" of Nazi crimes, said Bavendamm — the project's third director.

"Without the Nazi policies of expulsion and annihilation, 14 million Germans wouldn't have lost their homes as a result of flight and expulsion," she added. "But that doesn't change the fact that their expulsion by the Allies and the eastern and central European states in the aftermath of World War II was also an injustice."

In its efforts to provide context, the exhibition explores "forced migration as a phenomenon of modern Europe," including displacements during World War I, the arrival of Vietnamese "boat people" in West Germany in the 1970s, the fallout from the disintegration of Yugoslavia in 1990s and the European migration crisis of recent years. 

Exhibits include some 30 passports, including a German Jew's passport stamped with the letter "J" in the Nazi era, a "Nansen passport" for stateless refugees from 1937 and a modern-day provisional refugee passport. There is the diary of a girl from East Prussia, a territory Germany lost at the end of the war, chronicling sexual violence. 

There's also a bicycle used by a Syrian refugee to cross the Russian-Norwegian border in 2016. And there are audio accounts by people recounting their arrival in Germany.

Visitors are given a chronological account of Nazi atrocities, followed by the flight and expulsion of the Germans in the final months of the war and afterward. "At the same time, millions of Polish, Ukrainian, Hungarian or Slovakian citizens lost their homes in the time," curator Jochen Krueger said. "We tell their story here too."

The idea for a center commemorating the German expellees goes back to a call for a "center against expulsions" made in 1999 by Erika Steinbach, who at the time was the head of an organization representing the group and a lawmaker with Merkel's conservative party. It raised hackles in the following years in countries whose inhabitants suffered under brutal Nazi occupation.

Steinbach, who was deeply distrusted in neighboring Poland in particular, was kept off the board of the new center. In recent years, she has become a strident hard-right critic of Merkel, whose party she left in 2017, objecting in particular to her decision to allow in large numbers of migrants from Syria and elsewhere.

Steinbach wasn't invited to Monday's opening — because, according to Bavendamm, that was limited due to pandemic restrictions to people directly involved with the center. 

The new center opens to the public on Wednesday.