Photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Xinhua)

Photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Li Yuhui/Xinhua)

Photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Xinhua)

Photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Li Yuhui/Xinhua)

Aerial photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Chen Gang/Xinhua)

A monk visits the Preah Vihear Temple in Preah Vihear Province, Cambodia, Sept. 19, 2019. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Li Yuhui/Xinhua)

Photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Li Yuhui/Xinhua)

Photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Li Yuhui/Xinhua)

Tourists visit the Preah Vihear Temple in Preah Vihear Province, Cambodia, Sept. 19, 2019. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Xinhua)

Photo taken on Sept. 19, 2019 shows a view seen from a stone passageway of the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Xinhua)

Photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Li Yuhui/Xinhua)

Aerial photo taken on Sept. 19, 2019 shows the Preah Vihear Temple in Preah Vihear Province, Cambodia. The Preah Vihear Temple is located on the top of a cliff in the Dangrek Mountains in northern Cambodia. It was inscribed on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 2008. (Photo: Chen Gang/Xinhua)