A detailed picture of massive star formation in the Milky Way available through radio interferometers, ground-based optical/IR imaging systems, IR space telescopes and X-ray astronomical satellites, is compared with state-of-the-art numerical models of the massive star formation process. Analytical solutions are provided, in some cases helping to disentangle physical processes in the game. We investigate the initial conditions in the dark clouds - extremely dense, massive molecular cloud cores forming massive stars and massive star clusters. Direct measurements of the environment provide important insight into their formation mechanism. Mechanical and radiatively-driven feedback by winds and ionisation affect the surroundings of massive stars, forming expanding shells, unbinding stellar clusters and triggering secondary star formation in compressed layers.

This interim meeting of Work Package 2 of the CONSTELLATION network will review the above aspects of massive star formation and showcase the progress made over the past more than two years of cooperation.