The spectacular advances of modern astronomy have opened our horizon on an unexpected cosmos: a dark, mysterious universe, populated by enigmatic entities we know very little about, like black holes, or nothing at all, like dark matter and dark energy. Join Gianfranco Bertone as he discusses 'multimessenger astronomy', combining the traditional approach based on the observation of light from celestial objects, with a new method based on other 'messengers' – such as gravitational waves.