  In this thesis, we present new exact solutions of Einstein-Maxwell's field
equations, with the most general case being the dyonic Kerr-Newman black hole
in a Melvin-swirling universe, obtained analytically using the Ehlers-Harrison
transformations of the Ernst formalism. Subsequently, for each possible
sub-case, we analyze the presence of singularities and study some physical
properties. Finally, we examine their supersymmetry in the context of $N=2$,
$d=4$ Supergravity.
