A sightseeing bus is seen at the Unter den Linden Boulevard in Berlin, capital of Germany, April 28, 2022. (Xinhua/Ren Pengfei)

People ride bicycles at the Unter den Linden Boulevard in Berlin, capital of Germany, April 28, 2022. (Xinhua/Ren Pengfei)

People take a rest near the Unter den Linden Boulevard in Berlin, capital of Germany, April 28, 2022. (Xinhua/Ren Pengfei)

Photo taken on April 28, 2022 shows a road sign at the Unter den Linden Boulevard in Berlin, capital of Germany. (Xinhua/Ren Pengfei)

People visit the Pariser Platz at the east side of the Brandenburg Gate in Berlin, capital of Germany, April 28, 2022. (Xinhua/Ren Pengfei)

Photo taken on April 28, 2022 shows a road sign at the Unter den Linden Boulevard in Berlin, capital of Germany. (Xinhua/Ren Pengfei)

People take a rest at a restaurant near the Unter den Linden Boulevard in Berlin, capital of Germany, April 28, 2022. (Xinhua/Ren Pengfei)

People take a rest near the Unter den Linden Boulevard in Berlin, capital of Germany, April 28, 2022. (Xinhua/Ren Pengfei)

People ride bicycles at the Unter den Linden Boulevard in Berlin, capital of Germany, April 28, 2022. (Xinhua/Ren Pengfei)