  The virtual observatory (VO) is a collection of interoperable data archives,
tools and applications that together form an environment in which original
astronomical research can be carried out. The VO is opening up new ways of
exploiting the huge amount of data provided by the ever-growing number of
ground-based and space facilities, as well as by computer simulations. This
presentation summarises a variety of scientific results spanning various fields
of astronomy, obtained thanks to the VO, after highlighting its structure,
infrastructure and various capabilities.
