  We consider Kaluza Klein reductions of M-theory on the Z_N orbifold of the
spin bundle over S^3 along two different U(1) isometries. The first one gives
rise to the familiar ``large N duality'' of the N=1 SU(N) gauge theory in which
the UV is realized as the world-volume theory of N D6-branes wrapped on S^3,
whereas the IR involves N units of RR flux through an S^2. The second reduction
gives an equivalent version of this duality in which the UV is realized
geometrically in terms of an S^2 of A_{N-1} singularities, with one unit of RR
flux through the S^2. The IR is reached via a geometric transition and involves
a single D6 brane on a lens space S^3/Z_N or, alternatively, a singular
background (S^2\times R^4)/Z_N, with one unit of RR flux through S^2 and,
localized at the singularities, an action of their stabilizer group in the U(1)
RR gauge bundle, so that no massless twisted states occur. We also consider
linear sigma-model descriptions of these backgrounds.
