A bridge is a man-made path for the purpose of providing the passage over an obstacle. Generally, it consists of two main parts: Superstructure and substructure of bridge. The former contains the body of bridge and bridge deck. The latter contains piers, abutments and foundation.
Originally，the “bridge” referred to a kind of big tree. It was big enough to lie down over the river. The tree could link the two banks of the river. That was a Single-plank Bridge. Until now, solving the problem of crossing over the water or valleys is still the primary purpose for a bridge.
Bridges are built of stone, wood, bamboo, brick, etc. Bridges in ancient China can be divided into four categories, namely the arch, beam, cable suspension and floating bridges.
Throughout history, the Chinese people have built thousands of bridges, which have earned high reputation all over the world. Ancient bridges are crystallization of our ancestors’ wisdom and besides their practical functions, they also have great artistic value. Nowadays we still can enjoy the beauty of some famous ones, such as China’s four famous ancient bridges, namely Zhaozhou Bridge, Luoyang Bridge, Guangji Bridge and Lugou Bridge.