When a group of Mechanical Engineers team up to investigate the emerging field of Mechanical Metamaterials, they find that recent advancements in 3D printing technology are enabling scientists to prototype everything from better shields against blunt force trauma to cloaks that could render an object undetectable by SONAR sound waves! Meanwhile, a Nanoscientist discusses both the challenges and the promises of fabricating Mechanical Metamaterials. Having had a hand in the nano-imaging and fabrication efforts underway at Lawrence Berkeley and MIT, she is acutely aware of the challenges the come with 3D printing at such small size scales, but sees great opportunity three orders of magnitude up the size scale—which happens to be the sweet spot for Mechanical Metamaterials. With a growing body of evidence showing jaw dropping performance enhancements with the use of Mechanical Metamaterials, will the manufacturing technology catch up fast enough so we can one day see the benefits of this technology?