Since 2010 the experiments at the Large Hadron Collider LHC at CERN investigate particle physics at the highest collision energies ever achieved in a laboratory. The discovery of the scalar boson H predicted by the Brout-Englert-Higgs mechanism, was the result of a long and fascinating story at the LHC. Building up the experimental programme with this unique high-energy collider, and developing the very sophisticated detectors built and operated by worldwide collaborations, meant a huge scientific and human adventure, spanning more than three decades. The first part of this talk will recall the history of this project and illustrate some of the many milestones that finally led to the H discovery by the ATLAS and CMS collaborations 6 years ago with data collected at 7 and 8 TeV pp collision energies. In the second part, the focus of the talk will shift to new ATLAS results, including also a few very recent analyses from the ongoing 13 TeV run of the LHC. These concern both improved measurements of the fundamental properties of the H boson as well as examples of searches for physics beyond the Standard Model.