  Massive stars have a strong impact on their surroundings, in particular when
they produce a core-collapse supernova at the end of their evolution. In these
proceedings, we review the general evolution of massive stars and their
properties at collapse as well as the transition between massive and
intermediate-mass stars. We also summarise the effects of metallicity and
rotation. We then discuss some of the major uncertainties in the modelling of
massive stars, with a particular emphasis on the treatment of convection in 1D
stellar evolution codes. Finally, we present new 3D hydrodynamic simulations of
convection in carbon burning and list key points to take from 3D hydrodynamic
studies for the development of new prescriptions for convective boundary mixing
in 1D stellar evolution codes.
