Researchers from the UK's Durham University and Germany's Fraunhofer Institute claim they've come up with the world's first manufactured non-cuttable material, just 15 percent the density of steel, which they say could make for indestructible bike locks and lightweight armor.

The material, named Proteus, uses ceramic spheres in a cellular aluminum structure to foil angle grinders, drills and the like by creating destructive vibrations that blunt any cutting tools used against it. The researchers took inspiration from the tough, cellular skin of grapefruit and the hard, fracture-resistant aragonite shells of molluscs in their creation of the Proteus design.