Ming City Wall of Nanjing. [Photo/VGC]

Sept 5 marked the 650th anniversary of the start of construction on Nanjing's ancient city wall.

According to historical record, the first emperor of the Ming dynasty, Zhu Yuanzhang, ordered the city of Jiankang - the former name for Nanjing - to be expanded on Sept 5, 1366. Construction on the wall lasted over 20 years.

Today, the ancient wall has become a symbol of Nanjing. It is also one of China's largest national treasures. Hundreds of citizens gathered at the city wall to celebrate the occasion. Jin Taijin, a student whose own birthday falls on Sept 5, brought a painting of the city wall as a "birthday gift" for the historic structure.

"I hope it will stand by our side forever," Jin said of the wall.

According to Cao Fangqing, an official with the Center for Protection of the Nanjing City Wall, a document was submitted to the State Administration of Cultural Heritage this March, applying for the wall to become a World Cultural Heritage Site.

Cao hopes the city wall will become the second such site in Nanjing, after the Ming Palace.