  Advanced Virgo is the project to upgrade the Virgo interferometric detector
of gravitational waves, with the aim of increasing the number of observable
galaxies (and thus the detection rate) by three orders of magnitude. The
project is now in an advanced construction phase and the assembly and
integration will be completed by the end of 2015. Advanced Virgo will be part
of a network with the two Advanced LIGO detectors in the US and GEO HF in
Germany, with the goal of contributing to the early detections of gravitational
waves and to opening a new observation window on the universe. In this paper we
describe the main features of the Advanced Virgo detector and outline the
status of the construction.
