Nine of World Heritage list, Xu Xiao reports.

The classical gardens of Suzhou, Jiangsu province, which were former private estates, represent the highest level of China's traditional gardening and have set a benchmark for Chinese classical garden design.

The Suzhou gardens, which are renowned for their rich landscaping in a limited space, span thousands of years.

Historical documents said locals began to build gardens when the city, which was then known as Gusu, became the capital of the Wu Kingdom some 2,500 years ago.

The local gardening design matured in the Song Dynasty (960-1279) and flourished in the Ming (1368-1644) and Qing (1644-1911) Dynasties.

Today, there are more than 60 well-preserved classical gardens in Suzhou, 19 of which are open to the public.

The classical gardens feature landscapes mimicking natural scenery of rocks, hills and rivers, which also feature cleverly laid-out bridges, pavilions and pagodas as well as other structures - all in a very limited space of several hectares or less.

In 1997, nine of the gardens were included on the UNESCO World Heritage list. The following four represent the best of Suzhou's ancient gardening art.