The Anji Bridge is the world's oldest open-spandrel segmental arch bridge of stone construction. Credited to the design of a craftsman named Li Chun, the bridge was constructed in the years 595–605 during the Sui dynasty (581–618). Located in the southern part of Hebei Province, it is the oldest standing bridge in China.
The Anji bridge is about 50 metres (160 ft) long with a central span of 37.37 metres (122.6 ft). It stands 7.3 metres (24 ft) tall and has a width of 9 metres (30 ft). The arch covers a circular segment less than half of a semicircle (84°) and with a radius of 27.27 metres (89.5 ft), has a rise-to-span ratio of approximately 0.197 (7.3 to 37 metres (24 to 121 ft)).
The bridge is also commonly known as the Zhaozhou Bridge, after Zhao County, which was formerly known as Zhaozhou. Another name for the bridge is the Great Stone Bridge. It crosses the Xiaohe River south of the town of Zhaoxian, in Zhao County, approximately 52 kilometres (32 mi) southeast of the provincial capital Shijiazhuang. It is a pedestrian bridge and is currently open to the public.
According to en.wikipedia