赵州桥

zhào zhōu qiáozhaozhouqiao

1. Zhaozhou Bridge over Xiao River 洨河[Xiao2 He2] in Zhao county 趙縣|赵县[Zhao4 Xian4], Shijiazhuang, Hebei, dating back to the Sui dynasty 隋代[Sui2 dai4] (581-617) and the world's oldest extant stone arch bridge

Study it in Yanamino