  We construct an MSSM with three generations from the heterotic string
compactified on a smooth 6D internal manifold using Abelian gauge fluxes only.
The compactification space is obtained as a resolution of the T6/Z2xZ2xZ2-free
orbifold. The Z2-free involution of such a resolution breaks the SU(5) GUT
group down to the SM gauge group using a suitably chosen (freely acting) Wilson
line. Surprisingly, the spectrum on a given resolution is larger than the one
on the corresponding orbifold taking into account the branching and Higgsing
due to the blow-up modes. The existence of extra resolution states is closely
related to the fact that the resolution procedure is not unique. Rather, the
various resolutions are connected to each other by flop transitions.
