The HST survey of Magellanic-Cloud clusters and of their stellar
  populations
  A large number of intermediate-age (~1-2-Gyr old) globular clusters (GCs) in
the Large and the Small Magellanic Cloud (MC) exhibit either bimodal or
extended main-sequence (MS) turn off and dual red clump. Moreover, recent
papers have shown that the MS of the young clusters NGC1844 and NGC1856 is
either broadened or split. These features of the color-magnitude diagram (CMD)
are not consistent with a single isochrone and suggest that star clusters in
MCs have experienced a prolonged star formation, in close analogy with
Milky-Way GCs with multiple stellar populations. As an alternative, stellar
rotation or interacting binaries can be responsible of the CMD morphology. In
the following I will summarize the observational scenario and provide
constraints on the nature of the complex CMD of young and intermediate-age MC
clusters from our ongoing photometric survey with the Hubble Space Telescope.
