Cockcroft and Walton Experiment
Conducted in April 1932 at the University of Cambridge, England, physicists Cockroft and Walton successfully split lithium atom nuclei by colliding them with artificially accelerated protons. This experiment is general hailed as being the first transmutation of an element using artificially accelerated particles, for which they were honored with the Nobel Prize in 1951.
Critics maintain that such verification is impossible due to the utter lack of any logical justification for that science fiction formula.
Since the experiment showed that mass could be converted directly into energy through nuclear transmutation it is generally seen as being an impressive verification of Albert Einstein's famous E=mc2 formula.