The Zhaozhou Bridge (officially the Anji Bridge) in Zhao County, 52 kilometres southeast of Shijiazhuang, is not just the oldest surviving bridge in China — it is the oldest open-spandrel segmental arch bridge in the world. Built between 595 and 605 during the Sui dynasty by the engineer Li Chun, it crosses the Xiaohe River in a single 37-metre span using a segmented arch that distributes weight so efficiently that the bridge has survived, with periodic repairs, for nearly 1,400 years.
The structural ingenuity is the reason to come. The arch is not a full semicircle but a segment of a much larger circle, which lowers the profile and reduces the material needed. The spandrels — the triangular spaces between the arch and the roadway — are pierced by smaller arches, which reduces weight further and allows floodwater to pass. Western engineers did not achieve comparable results until the nineteenth century. The bridge works and you can see why.
The setting is unassuming — flat farmland, a modest river, a small park around the bridge — which makes the engineering feel stranger and more impressive. The stone balustrades have been replaced several times, but the structural arch is largely original. Entry is inexpensive and the site is rarely crowded on weekdays.