BERLIN — First lady Michelle Obama and daughters Malia and Sasha visited the Holocaust memorial in Berlin amid tight security.

Obama and her daughters spent about a half-hour Wednesday morning visiting the sea of 2,711 steles that comprise the memorial, according to Uwe Neumaerker, its director. They were guarded by helicopters hovering over the area, which was cleared of visitors, so the memorial “was totally silent and they were alone,” Neumaerker told JTA by phone following the visit. He said Obama and her daughters had a chance to wander among the tall, tomb-like concrete slabs.

“They were impressed that we Germans have such a memorial in the center of our city,” Neumaerker said, adding that the first lady “really has an aura.”

American-Jewish architect Peter Eisenman designed the memorial, which was opened to the public in May 2005 on the 60th anniversary of the end of World War II.

Also on the visit was Auma Obama, President Obama’s half-sister, about whose existence he reportedly learned of only after his father’s death in 1982. Auma Obama, 53, studied in Germany and lives in her native Kenya.

The visit took place as President Obama stopped in Berlin for meetings with Chancellor Angela Merkel and opposition leader Peer Steinbruck following the G-8 summit in Ireland. Obama was to address a crowd of some 4,000 guests at the Brandenburg Gate later in the day.

Around that time, all windows facing the site must remain closed, including the offices of members of parliament. Even movement in front of windows reportedly is banned.

Michelle Obama and her daughters were scheduled to stop at a memorial dedicated to the history of the Berlin Wall, which divided the eastern and western portions of the city and symbolized the Cold War between the communist Soviet Union and the United States for 28 years. The wall was torn down in 1989, and German unification soon followed.