People visit Maijishan Grottoes in Tianshui City, NW China

Tourists visit the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 30, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Zhang Keren)

Tourists visit the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 30, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Fan Peishen)

Tourists visit the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 29, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Fan Peishen)

This aerial photo shows the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 29, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Fan Peishen)

Tourists visit the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 30, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Zhang Keren)

Tourists visit the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 30, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Ma Ning)

Tourists visit the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 30, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Ma Ning)

Tourists view a tour route diagram at the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 30, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Fan Peishen)

Tourists visit the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 30, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Fan Peishen)

Tourists visit the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 30, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Zhang Keren)

This aerial photo shows the Maijishan Grottoes in Tianshui City, northwest China's Gansu Province, July 29, 2023. The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui. Two temporary sightseeing routes are provided to tourists between July 29 and Aug. 25 during the summer travel season. (Xinhua/Fan Peishen)