Virgo is a giant scientific instrument, build near Pisa in Italy. The associated international scientific collaboration includes laboratories from five countries: France and Italy (the two countries behind the project), the Netherlands, Poland and Hungary. The Virgo detector is a Michelson interferometer isolated from external disturbances (mirrors and instrumentation all suspended, laser beam under vacuum) and whose both arms are three km long. Virgo aims at achieving a direct detection of the gravitational waves predicted by general relativity.