  The closest examples of high-mass star birth occurs in deeply embedded
environments at kiloparsec distances. Although much progress has been made, an
observationally validated picture of the dominant processes which allows the
central hydrostatic object to grow in mass has yet to be established. The
observational technique of optical interferometry has demonstrated its
potential in the field of high-mass star formation by delivering a
milli-arcsecond infrared view on the complex accretion environment. We provide
an overview of the scientific results obtained with multi-aperture telescope
arrays and briefly discuss future instruments and their anticipated impact on
our understanding of massive young stellar objects.
