Endohedral fullerenes represent a novel family of carbon nanostructures, which are characterized by a robust fullerene cage with atoms, ions, or clusters trapped in its interior. Since the first separation of the endohedral metallofullerene La@C₈₂ in 1991, a large variety of endohedral structures have been isolated and their endohedral nature has been proved by experimental studies. Within the past two decades, the world of endohedral fullerenes was significantly enlarged by the clusterfullerenes and the new carbon cages including non-IPR (IPR=isolated pentagon rule)...