Over the past 20 years, physicists at CERN have perfected the art of creating and storing actual atoms of antimatter, enabling them to study it at a whole new level. In 2016 they have shown that the laws of physics are identical for antihydrogen and hydrogen. Read 'Laser excites antimatter atoms for first time' to learn how physicists verified identical laws of physics at work with antihydrogen.
Matter and antimatter annihilation is the most efficient reaction known. It releases energy which is proportional to the total matter and antimatter mass according to E=mc2. It produces large amounts of energy, intense photons and/or a less massive particle-antiparticle pair.