Metamaterials provide control over the material properties though engineering of their subwavelength elementary units, the meta-atoms. An electromagnetic wave impinging on a metamaterial induces the excitation of local currents whose distribution is defined by the meta-atoms architecture and the details of the electromagnetic wave, i.e., frequency, incidence angle and polarization, producing a far-field response that can be perceived much like a material property. Metamaterials have opened up the path to novel electromagnetic features, providing the most known, negative effective permeability and negative refractive index (usually achievable by combining negative effective permittivity and permeability) and the more recently investigated, sustaining toroidal excitations and topological photonic states. The enhanced electromagnetic wave manipulation enabled by metamaterial–based structures has led to fascinating applications which among else include ultrathin electromagnetic sheets for wavefront shaping, shielding and polarization control, software-defined wave control, graphene-based ultrafast modulators, topologically protected unidirectional propagation, energy harvesting. In this talk we will review basic principles of emerging metamaterial induced exotic phenomena and discuss interesting implementations in technologically relevant spectral areas, i.e., microwaves, THz and the near-IR / mid-IR.