Observing the universe with interferometric detectors for gravitational waves: status and perspectives

The first direct observations of Gravitational Waves signals with ground based large interferometers are opening a new era in astronomy and astrophysics, a century after the development of the General Relativity theory predicting their existence. Great improvements and experience have been acquired in operating the first generation instruments fixing some important parameters for future generations of detectors aimed to a continuous observation of Gravitational Waves emitted by black holes, neutron stars and other enigmatic sources of these weak signals. The importance of a worldwide network based on second generation of laser interferometers in localizing Gravitational Waves sources in the sky is here underlined. While an overview of the technological improvements performed in the construction of these sophisticated detectors is presented with particular emphasis to the Advanced VIRGO interferometer. This European experimental apparatus together with the two similar ones, Advanced LIGO in USA, will have the opportunity to increase of a factor 1000 the observable volume of the Universe.