Interpreting the complex CMDs of the Magellanic Clouds clusters
  The Magellanic Clouds host a large population of massive (> 10^4 Msun) star
clusters with ages ranging from a few Myr to 12 Gyr. In nearly all cases, close
inspection of their CMDs reveals features that deviate from expectations of a
classic isochrone. Young (< 2 Gyr) clusters show extended main sequence
turnoffs and in some cases split/dual main sequences. Clusters older than ~ 2
Gyr show splitting in the red giant branches when viewed in UV filters that are
sensitive to abundance variations (in particular nitrogen). A distribution of
stellar rotation rates appears to be the cause of the complex features observed
in the young and intermediate age clusters, while above ~ 2 Gyr the features
seem to be the same light-element abundance variations as observed in the
ancient Galactic globular clusters, a.k.a. "multiple populations". Here, we
provide an overview of current observations and their interpretations and
summarise possible links between all the classes of complexities, regardless of
age.
