An architect hoping to rebuild war-torn Mosul, Iraq, proposed a series of stunning 3D-printed bridges that would transform city using its own building debris as construction materials. /vincent.callebaut.org Photo

Architect Vincent Callebaut is the brainchild behind "The 5 Farming Bridges", which features 3D-printed housing units in the form of articulated spiders over the Tigris River. /vincent.callebaut.org Photo

Five 3D printers could construct 30 houses per day or nearly 55,000 housing units in five years spread over the five bridges. The concept was a winning project of the Rifat Chadirji Prize Competition, "Rebuilding Iraq's Liberated Areas: Mosul's Housing". /vincent.callebaut.org Photo