A visitor poses for a selfie with German Chancellor Angela Merkel (C) during the German Federal Government open day at German Chancellery in Berlin, capital of Germany, on Aug. 26, 2018. Major political institutions of German Federal Government, including German Chancellery, opened to the public on Saturday and Sunday. (Xinhua/Shan Yuqi)

A visitor sits in the cockpit of a fighter jet during the German Federal Government open day at German Federal Ministry of Defence in Berlin, capital of Germany, on Aug. 26, 2018. Major political institutions of German Federal Government, including German Chancellery, opened to the public on Saturday and Sunday. (Xinhua/Shan Yuqi)

People queue up to visit the German Chancellery during the German Federal Government open day in Berlin, capital of Germany, on Aug. 26, 2018. Major political institutions of German Federal Government, including German Chancellery, opened to the public on Saturday and Sunday. (Xinhua/Shan Yuqi)

A boy receives sweets from a military robot during the German Federal Government open day at German Federal Ministry of Defence in Berlin, capital of Germany, on Aug. 26, 2018. Major political institutions of German Federal Government, including German Chancellery, opened to the public on Saturday and Sunday. (Xinhua/Shan Yuqi)

Visitors are seen during the German Federal Government open day at German Chancellery in Berlin, capital of Germany, on Aug. 26, 2018. Major political institutions of German Federal Government, including German Chancellery, opened to the public on Saturday and Sunday. (Xinhua/Shan Yuqi)

Visitors are seen during the German Federal Government open day in front of the Press and Information Office of the Federal Government of Germany in Berlin, capital of Germany, on Aug. 26, 2018. Major political institutions of German Federal Government, including German Chancellery, opened to the public on Saturday and Sunday. (Xinhua/Shan Yuqi)

German Chancellor Angela Merkel (C) speaks during the German Federal Government open day at German Chancellery in Berlin, capital of Germany, on Aug. 26, 2018. Major political institutions of German Federal Government, including German Chancellery, opened to the public on Saturday and Sunday. (Xinhua/Shan Yuqi)