Our recent study of Galactic globular clusters using Ca and
Stromgren uvby photometry has shown that many globular clusters
have multiple red giant branch populations with distinct calcium
abundances, in sharp contrast to the widely accepted idea of
AGB pollution scenarios.
This suggests that these globular clusters, like \omega Cen,
are most likely the relics of more massive primeval
dwarf galaxies that merged and disrupted to form the proto-Galaxy.
In my talk, I will review current understanding of the multiple
populations in globular clusters and will present some highlights
of my survey.