ATLAS Overview and Main Results

An overview of the ATLAS experiment, its physics program and a selection of the most important results, based on the data taken in pp collisions at energies of 7 and 8 TeV in 2011 and 2012, respectively, is presented. The question of possible changes in our understanding of elementary particles physics, after a discovery of a new boson of the mass of ~125 GeV last summer, is addressed. During the current long shutdown, the Large Hadron Collider (LHC) will be upgraded to allow the LHC experiments to study pp collisions at the energy of ~13 TeV.The ATLAS plans for future analyses and measurements with the new data to be taken after 2015, are summarized