The prefabricated concrete 3D printed Zhaozhou Bridge appears in Tianjin on Oct. 21, 2019. The 3D printed Zhaozhou Bridge is designed and constructed by Ma Guowei’s team from the Hebei University of Technology. The bridge is 28.10 meters long, and 4.20 meters wide, while the span of the bridge arch is 18.04 meters. (Photo/Li Shengli)