This photo taken on Aug. 11, 2026 shows a lake in Gniezno, Poland. Gniezno is one of Poland's oldest cities and is known for its rich history and cultural heritage. (Photo by Aleksy Witwicki/Xinhua)

This photo taken on Aug. 11, 2026 shows a church in Gniezno, Poland. Gniezno is one of Poland's oldest cities and is known for its rich history and cultural heritage. (Photo by Aleksy Witwicki/Xinhua)

This photo taken on Aug. 11, 2026 shows a view of Gniezno, Poland. Gniezno is one of Poland's oldest cities and is known for its rich history and cultural heritage. (Photo by Aleksy Witwicki/Xinhua)

People walk on a street in Gniezno, Poland, Aug. 11, 2026. Gniezno is one of Poland's oldest cities and is known for its rich history and cultural heritage. (Photo by Aleksy Witwicki/Xinhua)

This photo taken on Aug. 11, 2026 shows a view of Gniezno, Poland. Gniezno is one of Poland's oldest cities and is known for its rich history and cultural heritage. (Photo by Aleksy Witwicki/Xinhua)

A man rides a bicycle past a shop in Gniezno, Poland, Aug. 11, 2026. Gniezno is one of Poland's oldest cities and is known for its rich history and cultural heritage. (Photo by Aleksy Witwicki/Xinhua)

This photo taken on Aug. 11, 2026 shows a view of Gniezno, Poland. Gniezno is one of Poland's oldest cities and is known for its rich history and cultural heritage. (Photo by Aleksy Witwicki/Xinhua)