The role of the bridge is for railroads, roads, channels, pipelines, pedestrians, etc. when crossing rivers, valleys, or other traffic routes.

It consists of three parts: superstructure, substructure, and foundation. The upper structure is the main structure to cross the barrier, including the bridge body and bridge deck.

The substructure includes piers and abutments. Foundation has an open excavation foundation, pile foundation, countersink foundation, caisson foundation, pipe column foundation, and bearing platform.

Support for the bridge span structure and the bridge pier or abutment support at the set of the force transfer device. Ancillary structures refer to the bridgehead lap, tapered berm, bank protection, diversion works, etc.

The birth of the bridge is to solve the traffic across the water or generate developers over the valley so that transportation or pedestrians on the bridge unimpeded. If from its earliest or the main function, the bridge should exclusively refer to the road across the water and air.

Modern bridges also play an important role in urban traffic, flat land bridges (overpasses), through the east and west, north and south.

It not only helps to relieve traffic congestion but also becomes a beautiful scenery of modern cities. China is the birthplace of the bridge. The bridge appeared in the Sui Dynasty.

In the Guinness World Records, the world's first bridge is the Lake Pontchartrain Bridge in the United States.

The Lake Pontchartrain Bridge is located on Lake Pontchartrain in Louisiana, USA, connecting New Orleans and Mandeville (Mandeville) with a total length of 38.4 kilometers.

So far, the ranking of the world's number one bridge has changed.

First place: Siduhe Special Bridge in Badong, Hubei, China (height: 560 meters)

The Sidu River Special Bridge is a single-span 900m steel truss stiffened girder suspension bridge with a 24.5m wide deck and a one-way slope, ranking first in the world.

The height difference from the top of the tower to the bottom of the valley is 560 meters. The rocket rope throwing system is used for the pilot cable crossing the deep canyon. The lifting of stiffened girders uses the 900m cable crane with the largest span in China.

Second place: Yanxigou Bridge in Qianjiang, Chongqing, China (height: 280m)

Located between Hongqiao Village and Zhengyang Town, Shuitian Township, Qianjiang District, Chongqing, the bridge is divided into two sides.

The total length of one side is 560 meters, of which the main bridge is 310 meters long, the main span is 150 meters, and the vertical height of the bridge and the valley floor is 280 meters.

Third place: France Milo Bridge (height: 270m)

Located on the Tarn valley in southern France, the vertical height of the bridge deck from the valley floor is 270 meters. Designed by British designer Norman Foster, it was completed and opened on December 17, 2004, after three years of construction, with then-French President Jacques Chirac making a special trip to cut the ribbon for it.