For the first time, scientists have successfully created optically active, chiral gold nanoparticles using amino acids and peptides. Many chemicals significant to life have mirror-image twins (left-handed and right-handed structures), a characteristic that is conventionally called chirality. This study describes how chirality, which is typically observed in organic molecules, can be extended to three-dimensional metallic nanostructures. This newly discovered synthesis method was described in Nature and was featured on the cover.