  A brief review to string and parton percolation is presented. After a short
introduction, the main consequences of percolation of color sources on the
following observables in A-A collisions: $J/\psi$ suppression, saturation of
the multiplicity, dependence on the centrality of the transverse momentum
fluctuations, Cronin effect and transverse momentum distributions, strength of
the two and three body Bose-Einstein correlations and forward-backward
multiplicity correlations, are presented. The behaviour of all of them can be
naturally explained by the clustering of color sources and the dependence of
the fluctuations of the number of these clusters on the density.
