Massive star formation as seen by optical interferometers

High-angular resolution observations are of key importance to massive star formation if we are to understand how young 
massive stars accrete mass. Testing numerical predictions of accreting massive stars requires observations at 
milli-arcsecond angular resolution.

We present an overview of the results to date in massive star formation using IR interferometry. All results are nearly 
exclusively obtained using the Very Large Telescope Interferometer. These results involve the near_IR beam-combiner 
AMBER and the mid-IR instrument MIDI. We will present the observational results and elaborate on the physical 
interpretation using radiative transfer modelling. The overview is based on the recent VLTI papers by  de Wit et al. (2008, 
2010, 2011). These results will be confronted with those of other massive YSOs obtained by our and other groups.