Chinese archaeologists have given a facelift to the world's longest ancient city wall, which winds through Nanjing, capital of Jiangsu province in east China.

In the past few months they have dug up wild plants, weeds and small trees growing along the wall and repaired cracks according to a detailed plan. They said moisture from the plants' roots would erode the structure. So far, 19.8 kilometers of the wall, a famous scenic spot in the city, have been preserved intact.

The original city wall was built over 2,400 years ago. The section that remains, with a total length of 33.67 kilometers, was built over 600 years ago. It ranges in height from 14 -20 meters and in width from 4 -10 meters. It has undergone five restorations in the past 50 years.

Nanjing is one of the most well-known ancient cities in the country, and was home to 10 dynasties. The Nanjing wall is 0.7 kilometers longer than Beijing's city wall and 1.7 kilometers longer than the wall in Paris. To better protect their wall, Nanjing City established the world's only city wall history museum.