Photo taken Aug. 10, 2019 shows a view of the Grand Canyon in Arizona, the United States. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

A lodge is seen near the Grand Canyon in Arizona, the United States, Aug. 9, 2019. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Photo taken Aug. 10, 2019 shows a view of the Grand Canyon in Arizona, the United States. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Photo taken Aug. 9, 2019 shows a view of the Grand Canyon in Arizona, the United States. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Photo taken Aug. 10, 2019 shows a view of the Grand Canyon in Arizona, the United States. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Tourists are seen along the Grand Canyon in Arizona, the United States, Aug. 9, 2019. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Photo taken Aug. 9, 2019 shows a view of the Grand Canyon in Arizona, the United States. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Tourists are seen along the Grand Canyon in Arizona, the United States, Aug. 9, 2019. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Photo taken Aug. 10, 2019 shows a view of the Grand Canyon in Arizona, the United States. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Photo taken Aug. 9, 2019 shows a view of the Grand Canyon in Arizona, the United States. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)

Photo taken Aug. 9, 2019 shows a view of the Grand Canyon in Arizona, the United States. The Grand Canyon, a steep-sided canyon carved by the Colorado River, is known for its visually overwhelming size and its colorful landscape. (Xinhua/Li Ying)