 Then a long upgrade to the second generation detector, called Advanced Virgo, started; its aim was to reach a sensitivity one order of magnitude better than the initial Virgo detector, allowing it to probe a volume of the Universe 1,000 times larger, making detections of gravitational waves more likely.Advanced Virgo started commissioning in 2016, joining the two advanced LIGO detectors ("aLIGO") for a first "engineering" observing period in May and June 2017.On 14 August 2017, LIGO and Virgo detected a signal, GW170814, which was reported on 27 September 2017.