Hundreds of ceramic tiles fell from the roof of a Centennial Tower in Anhai Province, China, and hit the ground near tourists at the site.
Witness footage showed the collapsed part of the roof, narrowly losing many people.
Local media quoted a statement from Fengyang County's Culture and Tourism Bureau, which said no one was injured in the incident, which occurred around 18:30 local time (BST 11:30 BST).
The Drum Tower (reportedly the largest in China) was built in 1375 during the Ming Dynasty, but was extensively rebuilt in 1995.
The county's officials are about 200 miles from the capital Beijing, and he said an investigation is underway, an article shared in China's instant messaging app WeChat.
Fengyang County is famous for Hongwu Emperor Zhu Yuanzhang, the founding emperor of Ming Dynasty.
Local authorities reportedly moved bystanders from the scene after the collapse and secured the area. A statement seen by local media added that the investigation will study the design and construction of the repair project.
The report said the supervision department was also sent to the site and experts were invited to assist in the investigation and verification process.
When repairs are carried out, the tower is closed and reopened on a later date announced.
