To enable negative refraction and related optical illusions, metamaterials are artificially engineered with unique properties that result from their internal physical structures, rather than their chemical composition. The concept is credited to an experiment conducted by the Soviet scientist Victor Veselago in 1968 to show that negatively refracting materials (as opposed to the typically observed positive refractive index) to create a negative index ‘superlens’ could be achieved when both electric permittivity (ε) and magnetic permeability (µ) of a material were negative. Thirty-three years after the conceptual proposal, the pioneering work of physicist John Pendry enabled the development of metamaterials as Veselago imagined—a composite material with negative refractive index providing greatly improved resolution.