  By analogy with the multi-vortices, we show that also multi-monopoles become
magnetic bags in the large n limit. This simplification allows us to compute
the spectrum and the profile functions by requiring the minimization of the
energy of the bag. We consider in detail the case of the magnetic bag in the
limit of vanishing potential and we find that it saturates the Bogomol'nyi
bound and there is an infinite set of different shapes of allowed bags. This is
consistent with the existence of a moduli space of solutions for the BPS
multi-monopoles. We discuss the string theory interpretation of our result and
also the relation between the 't Hooft large n limit of certain supersymmetric
gauge theories and the large n limit of multi-monopoles. We then consider
multi-monopoles in the cosmological contest and provide a mechanism that could
lead to their production.
