Zhao Zhouqiao, also known as Anji Bridge, is located on the Chanhe River in Zhao County, Hebei Province, across the north and south banks of the Chanhe River. Because the bridge body is made of stone, it is commonly known as "Dashiqiao". Built in the Sui Dynasty, from 595 to 605 AD, it was designed and built by the famous craftsman Li Chun. It is about 1500 years old. It is the earliest and best preserved ancient open-shouldered stone arch bridge in the world. In the long years, despite numerous floods, wind and rain, ice and snow erosion and eight earthquakes, it stood on the Qingshui River unscathed.

Zhao Zhouqiao Bridge is 50.82 meters long and 9.60 meters wide. The net span of the large arch is 37.37 meters long and the arch height is 7.23 meters. The characteristics of this bridge are:

1. The whole bridge has only one big arch, 37.4 meters long, which was the longest stone arch bridge in the world at that time. Bridge opening is not an ordinary semicircle, but like a bow, so there is no steep slope on the road above the big arch, which is convenient for horses and chariots to get up and down.

Second, there are two small arches on the shoulders of the big arch. This is a very creative design, which not only saves stones and reduces the weight of the bridge, but also increases the water flow in bridge opening and reduces the impact of floods on the bridge when the river surges. At the same time, add an arch on the arch to make the bridge more beautiful.

Three, the big arch is composed of 28 arch rings, just like so many arches with the same shape are put together to make an arc bridge opening. Each arch ring can independently support its weight. If one arch ring is broken, the other arches will not be affected.

Fourth, the structure of the whole bridge is symmetrical, which is very harmonious with the surrounding scenery; The stone pillars and slabs on the bridge are also beautifully carved. Zhang Kun of the Tang Dynasty said that looking at the bridge from a distance is like "the clouds rise at the beginning of the month, and Changhong draws a stream". Zhao Zhouqiao's superb technical level and immortal artistic value fully show the wisdom and strength of our working people. Zhao Zhouqiao's design concept and exquisite workmanship are not only second to none among ancient bridges in China, but also according to the research on bridges in the world, open-shouldered arch bridges like this did not appear in Europe until the middle of19th century, which was later than China 1200 years ago.