ATLAS is a particle physics experiment at the Large Hadron Collider (LHC) at CERN, that is searching for new discoveries in the head-on collisions of protons of extraordinarily high energy. It investigates a wide range of physics, from the search for the Higgs boson to extra dimensions and particles that could make up dark matter. Along with the other LHC general-purpose detector, CMS, ATLAS discovered the Higgs boson in 2012. Since the LHC was restarted earlier in 2015, with new records in proton energy being reached, further data are being collected that will allow in-depth investigation of the boson’s properties and thereby the origin of mass. In parallel, R&D activities are under way for the future, Phase-2 upgrades of the LHC, that will require completely new detectors.