Photo taken on May 21, 2019 shows a view of Changdeokgung Palace in Seoul, South Korea. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture as the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)

Photo taken on May 21, 2019 shows a view of Changdeokgung Palace in Seoul, South Korea. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture as the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)

People visit the Changdeokgung Palace in Seoul, South Korea, May 21, 2019. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture as the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)

A girl visits the Changdeokgung Palace in Seoul, South Korea, May 21, 2019. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture as the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)

People visit the Changdeokgung Palace in Seoul, South Korea, May 21, 2019. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture as the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)

People visit the Changdeokgung Palace in Seoul, South Korea, May 21, 2019. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture as the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)

People visit the Changdeokgung Palace in Seoul, South Korea, May 21, 2019. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture as the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)

People pose for a photo at the Changdeokgung Palace in Seoul, South Korea, May 21, 2019. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture as the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)

Photo taken on May 21, 2019 shows the Changdeokgung Palace in Seoul, South Korea. Changdeokgung Palace was listed as a UNESCO world heritage site in 1997 and is regarded as a masterpiece of architecture where the buildings are in harmony with the natural settings. (Xinhua/Wang Jingqiang)