  The apparent low power in the CMB temperature anisotropy power spectrum
derived from WMAP motivated us to consider the possibility of a non-trivial
topology. We focus on some simple spherical multi-connected manifolds
(Quaternionic, Octahedral, Truncated Cube and Poincare spaces) and discuss
their implications for the CMB in terms of the power spectrum, maps and the
correlation matrix. We also perform Bayesian model comparison against the
fiducial best-fit LCDM based both on the power spectrum and the correlation
matrix to assess their statistical significance. We find that the first year
power spectrum shows a slight preference for the Truncated Cube space, but the
3-year data show no evidence for any of these spaces.
