Photo taken on July 30, 2019 shows an exterior view of the Royal Palace of Brussels in Brussels, Belgium. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

People visit the Royal Palace of Brussels in Brussels, Belgium, July 30, 2019. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

Photo taken on July 30, 2019 shows an exterior view of the Royal Palace of Brussels in Brussels, Belgium. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

People visit the Royal Palace of Brussels in Brussels, Belgium, July 30, 2019. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

Photo taken on July 30, 2019 shows an interior view of the Royal Palace of Brussels in Brussels, Belgium. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

People visit the Royal Palace of Brussels in Brussels, Belgium, July 30, 2019. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

People visit the Royal Palace of Brussels in Brussels, Belgium, July 30, 2019. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

People visit the Royal Palace of Brussels in Brussels, Belgium, July 30, 2019. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

People visit the Royal Palace of Brussels in Brussels, Belgium, July 30, 2019. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

People visit the Royal Palace of Brussels in Brussels, Belgium, July 30, 2019. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)

People visit the Royal Palace of Brussels in Brussels, Belgium, July 30, 2019. The Royal Palace of Brussels is the Belgian King's administrative residence and main workplace. A tradition has been established since 1965 to open the Brussels Palace to the public every summer. From July 23 to August 25 this year, the palace can be visited free of charge except on Mondays. (Xinhua/Zhang Cheng)