Behold, the world’s first 3D-printed pedestrian bridge. Inaugurated December 14 in the park of Castilla-La Mancha in Alcobendas, just south of Madrid in Spain, the 40-foot-long is made up of eight parts, each one comprising layers of fused concrete powder micro-reinforced with thermoplastic polypropylene. The bridge is the brainchild of the Institute of Advanced Architecture of Catalonia, a Barcelona-based research and education center that worked with a contingent of architects, mechanical and structural engineers, and municipal representatives to bring the design to life.

Besides Acciona, the firm that performed most of the heavy lifting, both literally and figuratively, the institute’s most notable collaborator was Enrico Dini, the so-called “man who prints houses.” Dini developed D-Shape, a massive 3D printer that’s the first—and perhaps only—of its kind to bind sand into layer after layer of solid rock. With the Alcobendas bridge marking a civil-engineering first, the IAAC is hailing the construction as a “milestone for the construction sector at international level.”

Related: 3-D Printer Creates Entire Buildings From Solid Rock

But the designers didn’t neglect to tip a hat to the ur-architect: nature. The IAAC leveraged parametric modeling to not only reflect the “complexities of nature’s forms” but also optimize the distribution of raw materials.

“The computational design also allows to maximize the structural performance, being able to dispose the material only where it is needed, with total freedom of forms, maintaining the porosity thanks to the application of generative algorithms and challenging the traditional techniques of construction,” the institute said. The result? Less waste, greater stability, and one heck of a conversation piece.

+ Institute for Advanced Architecture of Catalonia