  This paper presents the cosmological applications of the quasispherical
Szekeres model. The quasispherical Szekeres model is an exact solution of the
Einstein field equations, which represents a time-dependent mass dipole
superposed on a monopole and therefore is suitable for modelling double
structures such as voids and adjourning galaxy superclusters. Moreover, as the
Szekeres model is an exact solution of the Einstein equations it enables
tracing light and estimation of the impact of cosmic structures on light
propagation. This paper presents the evolution of a void and adjourning
supercluster and also reports on how the Szekeres model might be employed
either for the estimation of mass of galaxies clusters or for the estimation of
the luminosity distance.
