Scientists at the European Organization for Nuclear Research near Geneva, have for the first time trapped atoms of anti-matter.
Thirty eight antihydrogen atoms were each held for a fraction of a second.
Writing in the journal Nature, the CERN researchers say they believe the breakthrough will help physicists understand the nature and origins of the universe.
The BBC's Science Correspondent says antihydrogen has been produced before, but it was instantly destroyed when it encountered normal matter.
The team says the ability to study such antimatter atoms will allow previously impossible tests of fundamental tenets of physics.
The current "standard model" of physics holds that each particle - protons, electrons, neutrons and a zoo of more exotic particles - has its mirror image antiparticle.
However, one of the great mysteries in physics is why our world is made up overwhelmingly of matter, rather than antimatter; the laws of physics make no distinction between the two and equal amounts should have been created at the Universe's birth.
The team proved that among their 10 million antiprotons and 700 million positrons, 38 stable atoms of antihydrogen were formed, lasting about two tenths of a second each.
Their next task is to produce more atoms, lasting longer in the trap, in order to study them more closely.