  In this thesis we will focus on Einstein's interpretation of gravity. We will
examine how the most famous equations in cosmology are derived from GR and also
some results of cosmological significance. We will see how combining that with
observational data forces us to consider some form of dark energy or vacuum
energy. So we will conclude with some of the more well-known models for dark
energy and examine how the dynamics of dark energy can lead us to the so-called
cosmological inflation.
