Optical space in metamaterials may be engineered to mimic the landscape of a multidimensional Universe which has regions of different topology and different effective dimensionality. The "metamaterial landscape" may include regions in which one or two spatial dimensions are compactified. Nonlinear optics of metamaterials in these regions mimics either U(1) or SU(2) Kaluza-Klein theories having one or more kinds of effective charges. As a result, novel "photon blockade" nonlinear optical metamaterial devices may be realized. Topology-changing phase transitions in such metamaterials lead to considerable particle creation perceived as flashes of light, thus providing a toy model of birth of an individual physical Universe.

13 pages, 2 figures, this version is accepted for publication in the Journal of Optics