Astrophysical observations at all scales provide indisputable evidence for the existence of an invisible and dominant mass component in the observable universe. The nature of this dark matter remains one of the greatest challenges of modern physics. The leading hypothesis is that dark matter is made of new elementary particles, with a vast range of masses and interaction cross-sections with normal matter. A well-motivated class of candidates are Weakly Interacting Massive Particles (WIMPs). One way to search for WIMPs is through their scattering off atomic nuclei in low background detectors placed deep underground.
I will discuss the XENON1T dark matter experiment ongoing at the Gran Sasso Laboratory, the first to use thousands of kilograms of liquid xenon as WIMP target and detector material. A first search with XENON1T has demonstrated an unprecedented low background and the best sensitivity over a wide range of WIMP masses.